Catalyst system

ABSTRACT

The present invention provides a catalyst system capable of catalyzing the carbonylation of an ethylenically unsaturated compound, which system is obtainable by combining:
     a) a metal of Group VIB or Group VIIIB or a compound thereof,   b) a bidentate phosphine, arsine or stibine ligand, and   c) an acid,
 
wherein the ligand is present in at least a 2:1 molar excess compared to the metal or the metal in the metal compound, and that the acid is present in at least a 2:1 molar excess compared to the ligand, a process for the carbonylation of an ethylenically unsaturated compound, a reaction medium, and use of the system.

The present invention relates to a novel catalyst system, a novelcarbonylation reaction medium and a process for the carbonylation ofethylenically unsaturated compounds using a novel catalyst system.

The carbonylation of ethylenically unsaturated compounds using carbonmonoxide in the presence of an alcohol or water and a catalyst systemcomprising a Group VIII metal, eg. palladium, and a phosphine ligand eg.an alkyl phosphine cycloalkyl phosphine, aryl phosphine, pyridylphosphine or bidentate phosphine, has been described in numerousEuropean patents and patent applications, eg. EP-A-0055875,EP-A-04489472, EP-A-0106379, EP-A-0235864, EP-A-0274795, EP-A-0499329,EP-A-0386833, EP-A-0441447, EP-A-0489472, EP-A-0282142, EP-A-0227160,EP-A-0495547 and EP-A-0495548. In particular, EP-A-0227160, EP-A-0495547and EP-A-0495548 disclose that bidentate phosphine ligands providecatalyst systems which enable higher reaction rates to be achieved.

WO 96/19434 discloses a bridging group in the form of an optionallysubstituted aryl moiety, linked to the said phosphorous atoms viaavailable adjacent carbon atoms on the said aryl moiety. Such a ligandis more stable and leads to reaction rates which are significantlyhigher than those previously disclosed and produces little or noimpurities for the carbonylation of ethylene. Each phosphorous atom inthe said ligand is also linked to two tertiary carbon atoms.

However, conventional metal-catalysed reactions, such as those describedin WO 96/19434 tend to suffer from the drawback that the catalyst tendsto de-activate over the course of a period of continuous operation asthe palladium compound is reduced to palladium metal, this contributingto the economic viability of the process. WO 01/10551 addressed thisproblem via the use of stabilising compounds such as polymericdispersants in the reaction medium, thus improving in the recovery ofmetal which has been lost from the catalyst system.

Although catalyst systems have been developed which exhibit reasonablestability during the carbonylation process and permit relatively highreaction rates to be achieved, there still exists a need for improvedcatalyst systems. Suitably, the present invention aims to provide animproved catalyst for carbonylating ethylenically unsaturated compounds.

J. Mol. Cat. A 204-205 (2003) pgs 295-303 suggests that a relativeincrease in the ligand concentration, for example by the addition ofmore ligand, has a detrimental effect on productivity. Similar resultsare reported in J. Mol. Cat. A. Chem. 110 (1996) pgs 13-23 and J. Mol.Cat. A. Chem. 151 (2000) pgs 47-59.

Moreover, WO-A-01/72697 describes a process for the carbonylation ofpentenenitrile but teaches that there are disadvantages associated atrelatively high acid:palladium ratios. The authors state that thedisadvantages occur because high acid concentration conditions arecorrosive and more ligand degradation results from quaternisation withthe acid and the olefinic compound.

WO-A-01/68583 discloses a process for the carbonylation of ethylenicallyunsaturated compounds using phosphine-based bidentate ligands. However,this disclosure is directed towards the use of relatively low acidlevels, leading to low acid:ligand values. Moreover, the ligand:metalratios are low. WO-A-03/040159 similarly discloses low acid:ligand andligand:metal ratios.

WO-A-98/45040 discloses catalyst systems comprising palladium compoundand bidentate phosphorus ligands. However, acid:ligand ratios of lessthan 1:1 are taught.

Finally, WO-A-01/72697 discloses a process for the preparation of a5-cyanovaleric acid by carbonylation of a pentenenitrile. The disclosurepoints out the disadvantages in using high acid concentrations andteaches towards the use of relatively low acid levels.

Hence, an aim of the present invention is to seek to establish acatalyst system wherein the levels of ligand and acid are relativelyhigh, but wherein the disadvantages of the prior art noted hereinbeforeare addressed and alleviated, at least to some extent, the aforesaidbeing one object of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows TON versus acid:ligand mol ratio.

FIG. 2 shows TON versus amount of methanesulphonic acid present free inthe reactor.

FIG. 3 shows Pd amount in solution versus amount of methanesulphonicacid.

DESCRIPTION

According to the present invention there is provided a catalyst system,a process for the carbonylation of an ethylenically unsaturatedcompound, a reaction medium, and use as set forth in the appendedclaims.

Preferred features of the invention will be apparent from the dependentclaims, and the description which follows.

According to a first aspect, the present invention provides a catalystsystem capable of catalysing the carbonylation of an ethylenicallyunsaturated compound, which system is obtainable by combining:

a) a metal of Group VIB or Group VIIIB or a compound thereof,

b) a bidentate phosphine, arsine, or stibine ligand, preferably abidentate phosphine ligand, and

c) an acid,

wherein said ligand is present in at least a 2:1 molar excess comparedto said metal or said metal in said metal compound, and that said acidis present in at least a 2:1 molar excess compared to said ligand.

Typically, component b) is a bidentate phosphine, arsine, or stibine.

Suitably, all of components a) to c) of the catalyst system can be addedin situ to the reaction vessel wherein the carbonylation is to takeplace. Alternatively, the components a) to c) can be added sequentiallyin any order to form the catalyst system, or in some specified order,either directly into the vessel or outside the vessel and then added tothe vessel. For instance, the acid component c) may first be added tothe bidentate ligand component b), to form a protonated ligand, and thenthe protonated ligand can be added to the metal or compound thereof(component a)) to form the catalyst system. Alternatively, the ligandcomponent b) and metal or compound thereof (component a)) can be mixedto form a chelated metal compound, and the acid (component c)) is thenadded. Alternatively, any two components can be reacted together to forman intermediate moiety which is then either added to the reaction vesseland the third component added, or is first reacted with the thirdcomponent and then added to the reaction vessel.

As such, the present invention is directed to a catalyst system whereinthe relative molar concentrations of both the bidentate ligand and theacid are at levels in excess of those previously envisaged, leading tosurprising and unexpected advantages when using the catalyst system inthe carbonylation of ethylenically unsaturated compounds, and thealleviation or at least reduction of at least some of the disadvantagesof the prior art systems. In particular, the use of a catalyst system ofthe present invention leads at least to a more stable system, increasedreaction rates, and improved turnover numbers in carbonylation reactionsof ethylenically unsaturated compounds.

As stated above, the ligand is present in the catalyst system, orprecursor thereto, in such quantity that the ratio of said ligand to thesaid metal (i.e. component b) to component a)) is at least a 2:1 molarratio. Preferably, the ratio of said ligand to the said metal is greaterthan a 2:1 molar ratio, more preferably in the range 2:1 to 1000:1, evenmore preferably in the range 2.5:1 to 1000:1, yet more preferably in therange 3:1 to 1000:1, even more preferably in the range 5:1 to 750:1,more preferably in the range 7:1 to 1000:1, especially in the range 8:1to 900:1, still more preferably in the range 10:1 to 500:1, yet stillmore preferably in the range 20:1 to 400:1, even more preferably in therange 50:1 to 250:1, most preferably in the range in excess of 50:1, forexample 51:1 and upwards, more specifically 51:1 to 250:1 or even to1000:1. Alternatively, the said ratio can be in the range 15:1 to 45:1,preferably 20:1 to 40:1, more preferably 25:1 to 35:1.

As stated above, the acid is present in the catalyst system, orprecursor thereto, in such quantity that the ratio of said acid to thesaid ligand (i.e. component c) to component b)) is at least a 2:1 molarratio. Preferably, the ratio of said acid to the said ligand is greaterthan a 2:1 molar ratio, more preferably in the range 2:1 to 100:1, evenmore preferably in the range 4:1 to 100:1, yet more preferably in therange 5:1 to 95:1, still more preferably in the range greater than 5:1to 95:1, yet more preferably in the range greater than 5:1 to 75:1, morepreferably in the range 10:1 to 50:1, even more preferably in the range20:1 to 40:1, still more preferably in the range greater than 20:1 to40:1 (e.g. 25:1 to 40:1, or 25:1 to less than 30:1), more preferably inexcess of 30:1, suitably with any of the upper limits providedhereinbefore (e.g. 30:1 to 40:1, or 50:1, etc.), or more preferably inexcess of 35:1, yet more preferably in excess of 37:1, suitably eitherwith any of the upper limits provided hereinbefore. Each of the rangesin this paragraph can be used in conjunction with each of the ligand tometal ratio ranges disclosed hereinabove, i.e. ratios of component b) tocomponent a).

By “acid”, we mean an acid or salt thereof, and references to acidshould be construed accordingly.

The advantages in working within the ligand to metal, and acid to ligandratios, set out above are manifest in that the stability of the catalystsystem is improved, as evidenced by increases in the turnover number(TON) of the metal. By improving the stability of the catalyst system,the usage of metal in the carbonylation reaction scheme is kept to aminimum.

Without wishing to be bound by theory, it is believed that by workingwithin the specific ratio ranges noted herein, it is surprisingly foundthat the ligand component of the catalyst system is protected againstinadvertent aerial oxidation (in instances where there is any ingress ofair into the reaction system), and the overall stability of the catalystsystem is improved, thus keeping the usage of the metal component of thecatalyst system to a minimum. Moreover, the forward reaction rate of thereaction is surprisingly improved.

In effect, the level of acid should be such that for the particularbidentate ligand employed, the level of acid should be such thatphosphine, arsine or stibine is fully protonated. Hence, to show theimproved effects, the level of ligand should be above some minimumlevel, as given by the ligand:metal molar ratio, and the level of acidshould be above some minimum level with respect to the level of ligandpresent to encourage protonation, as given by the acid:ligand molarratio.

Preferably, the acid is present in the catalyst system, or precursorthereto, in such quantity that the molar ratio of said acid to saidmetal (i.e. component c) to component a)) is at least 4:1, morepreferably from 4:1 to 100000:1, even more preferably 10:1 to 75000:1,yet more preferably 20:1 to 50000:1, yet still more preferably 25:1 to50000:1, yet still more preferably 30:1 to 50000:1, yet even morepreferably 40:1 to 40000:1, still more preferably 100:1 to 25000:1, morepreferably 120:1 to 25000:1, more preferably 140:1 to 25000:1, yet stillmore preferably 200:1 to 25000:1, most preferably 550:1 to 20000:1, orgreater than 2000:1 to 20000:1. Alternatively, the said ratio can be inthe range 125:1 to 485:1, more preferably 150:1 to 450:1, even morepreferably 175:1 to 425:1, yet even more preferably 200:1 to 400:1, mostpreferably 225:1 to 375:1. Each of these ranges in this paragraph can beused in conjunction with each of the ligand to metal ratio rangesdisclosed hereinabove, i.e. ratios of component b) to component a),and/or each of the acid to ligand ratio ranges disclosed hereinabove,i.e. ratios of component c) to component b).

For the avoidance of any doubt, all of the aforementioned ratios andratio ranges apply to all of the ligand embodiments set out in moredetail hereinafter.

In one embodiment of the present invention, the bidentate phosphineligand is of general formula (I)

wherein:Ar is a bridging group comprising an optionally substituted aryl moietyto which the phosphorus atoms are linked on available adjacent carbonatoms;A and B each independently represent lower alkylene;K, D, E and Z are substituents of the aryl moiety (Ar) and eachindependently represent hydrogen, lower alkyl, aryl, Het, halo, cyano,nitro, OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁵R²⁶,C(S)R²⁵R²⁶, SR²⁷, C(O)SR²⁷, or -J-Q³(CR¹³(R¹⁴)(R¹⁵)CR¹⁶(R¹⁷)(R¹⁸) whereJ represents lower alkylene; or two adjacent groups selected from K, Z,D and E together with the carbon atoms of the aryl ring to which theyare attached form a further phenyl ring, which is optionally substitutedby one or more substituents selected from hydrogen, lower alkyl, halo,cyano, nitro, OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁵R²⁶,C(S)R²⁵R²⁶, SR²⁷ or C(O)SR²⁷;R¹³ to R¹⁸ each independently represent hydrogen, lower alkyl, aryl, orHet, preferably each independently represent lower alkyl, aryl, or Het;R¹⁹ to R²⁷ each independently represent hydrogen, lower alkyl, aryl orHet;R¹ to R¹² each independently represent hydrogen, lower alkyl, aryl, orHet, preferably each independently represent lower alkyl, aryl, or Het;Q¹, Q² and Q³ (when present) each independently represent phosphorous,arsenic or antimony and in the latter two cases references to phosphineor phosphorous above are amended accordingly, with preferably both Q¹and Q² representing phosphorus, more preferably all of Q¹, Q² and Q³(when present) representing phosphorus.

Suitably, the bidentate phosphines of the invention should preferably becapable of bidentate coordination to the Group VIB or Group VIIIB metalor compound thereof, more preferably to the preferred palladium.

Preferably, when K, D, E or Z represent -J-Q³(CR¹³(R¹⁴)(R¹⁵))CR¹⁶(R¹⁷)(R¹⁸), the respective K, D, E or Z is on thearyl carbon adjacent the aryl carbon to which A or B is connected or, ifnot so adjacent, is adjacent a remaining K, D, E or Z group which itselfrepresents -J-Q³(CR¹³(R¹⁴)(R¹⁵))CR¹⁶(R¹⁷)(R¹⁸).

Specific but non-limiting examples of bidentate ligands within thisembodiment include the following:1,2-bis-(di-tert-butylphosphinomethyl)benzene,1,2-bis-(di-tert-pentylphosphinomethyl)benzene,1,2-bis-(di-tert-butylphosphinomethyl)naphthalene. Nevertheless, theskilled person in the art would appreciate that other bidentate ligandscan be envisaged without departing from the scope of the invention.

The term “Ar” or “aryl” when used herein, includes five-to-ten-membered,preferably, six-to-ten membered carbocyclic aromatic groups, such asphenyl and naphthyl, which groups are optionally substituted with, inaddition to K, D, E or Z, one or more substituents selected from aryl,lower alkyl (which alkyl group may itself be optionally substituted orterminated as defined below), Het, halo, cyano, nitro, OR¹⁹, OC(O)R²⁰,C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁵R²⁶, SR²⁷, C(O)SR²⁷ or C(S)NR²⁵R²⁶wherein R¹⁹ to R²⁷ each independently represent hydrogen, aryl or loweralkyl (which alkyl group may itself be optionally substituted orterminated as defined below). Furthermore, the aryl moiety may be afused polycyclic group, e.g. naphthalene, biphenylene or indene.

By the term “a metal of Group VIB or Group VIIIB” we include metals suchas Cr, Mo, W, Fe, Co, Ni, Ru, Rh, Os, Ir, Pt and Pd. Preferably, themetals are selected from Ni, Pt and Pd. More preferably, the metal isPd. For the avoidance of doubt, references to Group VIB or VIIIB metalsherein should be taken to include Groups 6, 8, 9 and 10 in the modernperiodic table nomenclature.

The term “Het”, when used herein, includes four-to-twelve-membered,preferably four-to-ten-membered ring systems, which rings contain one ormore heteroatoms selected from nitrogen, oxygen, sulphur and mixturesthereof, and which rings may contain one or more double bonds or benon-aromatic, partly aromatic or wholly aromatic in character. The ringsystems may be monocyclic, bicyclic or fused. Each “Het” groupidentified herein is optionally substituted by one or more substituentsselected from halo, cyano, nitro, oxo, lower alkyl (which alkyl groupmay itself be optionally substituted or terminated as defined below)OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁵R²⁶, SR²⁷, C(O)SR²⁷or C(S)NR²⁵R²⁶ wherein R¹⁹ to R²⁷ each independently represent hydrogen,aryl or lower alkyl (which alkyl group itself may be optionallysubstituted or terminated as defined below). The term “Het” thusincludes groups such as optionally substituted azetidinyl, pyrrolidinyl,imidazolyl, indolyl, furanyl, oxazolyl, isoxazolyl, oxadiazolyl,thiazolyl, thiadiazolyl, triazolyl, oxatriazolyl, thiatriazolyl,pyridazinyl, morpholinyl, pyrimidinyl, pyrazinyl, quinolinyl,isoquinolinyl, piperidinyl, pyrazolyl and piperazinyl. Substitution atHet may be at a carbon atom of the Het ring or, where appropriate, atone or more of the heteroatoms.

“Het” groups may also be in the form of an N oxide.

The term “lower alkyl” when used herein, means C₁ to C₁₀ alkyl andincludes methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl groups.Unless otherwise specified, alkyl groups may, when there is a sufficientnumber of carbon atoms, be linear or branched, be saturated orunsaturated, be cyclic, acyclic or part cyclic/acyclic, and/or besubstituted or terminated by one or more substituents selected fromhalo, cyano, nitro, OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²², NR²³R²⁴,C(O)NR²⁵R²⁶, SR²⁷, C(O)SR²⁷, C(S)NR²⁵R²⁶, aryl or Het, wherein R¹⁹ toR²⁷ each independently represent hydrogen, aryl or lower alkyl, and/orbe interrupted by one or more oxygen or sulphur atoms, or by silano ordialkylsilcon groups.

Lower alkyl groups or alkyl groups which R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸,R⁹, R¹⁰, R¹¹, R¹², R¹³, R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹, R²⁰, R²¹, R²²,R²³, R²⁴, R²⁵, R²⁶, R²⁷, K, D, E and Z may represent and with which aryland Het may be substituted, may, when there is a sufficient number ofcarbon atoms, be linear or branched, be saturated or unsaturated, becyclic, acyclic or part cyclic/acyclic, and/or be interrupted by one ormore of oxygen or sulphur atoms, or by silano or dialkylsilicon groups,and/or be substituted by one or more substituents selected from halo,cyano, nitro, OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁵R²⁶,SR²⁷, C(O)SR²⁷, C(S)NR²⁵R²⁶, aryl or Het wherein R¹⁹ to R²⁷ eachindependently represent hydrogen, aryl or lower alkyl.

Similarly, the term “lower alkylene” which A, B and J (when present)represent in a compound of formula I, when used herein, includes C₁ toC₁₀ groups which are bonded to other moieties at least at two places onthe group and is otherwise defined in the same way as “lower alkyl”.

Halo groups with which the above-mentioned groups may be substituted orterminated include fluoro, chloro, bromo and iodo.

Where a compound of a formula herein contains an alkenyl group, cis (E)and trans (Z) isomerism may also occur. The present invention includesthe individual stereoisomers of the compounds of any of the formulasdefined herein and, where appropriate, the individual tautomeric formsthereof, together with mixtures thereof. Separation of diastereoisomersor cis and trans isomers may be achieved by conventional techniques,e.g. by fractional crystallisation, chromatography or H.P.L.C. of astereoisomeric mixture of a compound one of the formulas or a suitablesalt or derivative thereof. An individual enantiomer of a compound ofone of the formulas may also be prepared from a corresponding opticallypure intermediate or by resolution, such as by H.P.L.C. of thecorresponding racemate using a suitable chiral support or by fractionalcrystallisation of the diastereoisomeric salts formed by reaction of thecorresponding racemate with a suitable optically active acid or base, asappropriate.

All stereoisomers are included within the scope of the process of theinvention.

It will be appreciated by those skilled in the art that the compounds offormula I may function as ligands that coordinate with the Group VIB orGroup VIIIB metal or compound thereof in the formation of the catalystsystem of the invention. Typically, the Group VIB or Group VIIIB metalor compound thereof coordinates to the one or more phosphorous, arsenicand/or antimony atoms of the compound of formula I.

Preferably, R¹ to R¹⁸ each independently represent lower alkyl or aryl.More preferably, R¹ to R¹⁸ each independently represent C₁ to C₆ alkyl,C₁-C₆ alkyl phenyl (wherein the phenyl group is optionally substitutedas defined herein) or phenyl (wherein the phenyl group is optionallysubstituted as defined herein). Even more preferably, R¹ to R¹⁸ eachindependently represent C₁ to C₆ alkyl, which is optionally substitutedas defined herein. Most preferably, R¹ to R¹⁸ each representnon-substituted C₁ to C₆ alkyl such as methyl, ethyl, n-propyl,iso-propyl, n-butyl, iso-butyl, tert-butyl, pentyl, hexyl andcyclohexyl.

Alternatively, or additionally, each of the groups R¹ to R³, R⁴ to R⁶,R⁷ to R⁹, R¹⁰ to R¹², R¹³ to R¹⁵ or R¹⁶ to R¹⁸ together independentlymay form cyclic structures such as 1-norbornyl or 1-norbornadienyl.Further examples of composite groups include cyclic structures formedbetween R¹-R¹⁸. Alternatively, one or more of the groups may represent asolid phase to which the ligand is attached.

In a particularly preferred embodiment of the present invention R¹, R⁴,R⁷, R¹⁰, R¹³ and R¹⁶ each represent the same lower alkyl, aryl or Hetmoiety as defined herein, R², R⁵, R⁸, R¹¹, R¹⁴ and R¹⁷ each representthe same lower alkyl, aryl or Het moiety as defined herein, and R³, R⁶,R⁹, R¹², R¹⁵ and R¹⁸ each represent the same lower alkyl, aryl or Hetmoiety as defined herein. More preferably R¹, R⁴, R⁷, R¹⁰, R¹³ and R¹⁶each represent the same C₁-C₆ alkyl, particularly non-substituted C₁-C₆alkyl, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl,tert-butyl, pentyl, hexyl or cyclohexyl; R², R⁵, R⁸, R¹¹, R¹⁴ and R¹⁷each independently represent the same C₁-C₆ alkyl as defined above; andR³, R⁶, R⁹, R¹², R¹⁵ and R¹⁸ each independently represent the same C₁-C₆alkyl as defined above. For example: R¹, R⁴, R⁷, R¹⁰, R¹³ and R¹⁶ eachrepresent methyl; R², R⁵, R⁸, R¹¹, R¹⁴ and R¹⁷ each represent ethyl;and, R³, R⁶, R⁹, R¹², R¹⁵ and R¹⁸ each represent n-butyl or n-pentyl.

In an especially preferred embodiment of the present invention each R¹to R¹⁸ group represents the same lower alkyl, aryl, or Het moiety asdefined herein. Preferably, each R¹ to R¹⁸ represents the same C₁ to C₆alkyl group, particularly non-substituted C₁-C₆ alkyl, such as methyl,ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, pentyl,hexyl and cyclohexyl. Most preferably, each R¹ to R¹⁸ represents methyl.

In the compound of formula I, preferably each Q¹, Q² and Q³ (whenpresent) are the same. Most preferably, each Q¹, Q² and Q³ (whenpresent) represents phosphorous.

Preferably, in the compound of formula I, A, B and J (when present) eachindependently represent C₁ to C₆ alkylene which is optionallysubstituted as defined herein, for example with lower alkyl groups.Preferably, the lower alkylene groups which A, B and J (when present)represent are non-substituted. A particular preferred lower alkylenewhich A, B and J may independently represent is —CH₂— or —C₂H₄—. Mostpreferably, each of A, B and J (when present) represent the same loweralkylene as defined herein, particularly —CH₂—.

Preferably, in the compound of formula I when K, D, E or Z does notrepresent -J-Q³(CR¹³(R¹⁴)(R¹⁵))CR¹⁵ (R¹⁷)(R¹⁸), K, D, E or Z representshydrogen, lower alkyl, phenyl or lower alkylphenyl. More preferably, K,D, E or Z represent hydrogen, phenyl, C₁-C₆ alkylphenyl or C₁-C₆ alkyl,such as methyl, ethyl, propyl, butyl, pentyl and hexyl. Most preferably,K, D, E or Z represents hydrogen.

Preferably, in the compound of formula I when K, D, E and Z togetherwith the carbon atoms of the aryl ring to which they are attached do notform a phenyl ring, K, D, E and Z each independently represent hydrogen,lower alkyl, phenyl or lower alkylphenyl. More preferably, K, D, E and Zeach independently represent hydrogen, phenyl, C₁-C₆ alkylphenyl orC₁-C₆ alkyl, such as methyl, ethyl, propyl, butyl, pentyl and hexyl.Even more preferably, K, D, E and Z represent the same substituent. Mostpreferably, they represent hydrogen.

Preferably, in the compound of formula I when K, D, E or Z does notrepresent -J-Q³(CR¹³(R¹⁴)(R¹⁵))CR¹⁶(R¹⁷)(R¹⁸) and K, D, E and Z togetherwith the carbon atoms of the aryl ring to which they are attached do notform a phenyl ring, each of K, D, E and Z represent the same groupselected from hydrogen, lower alkyl, aryl, or Het as defined herein;particularly hydrogen or C₁-C₆ alkyl (more particularly unsubstitutedC₁-C₆ alkyl), especially hydrogen.

Preferably, in the compound of formula I when two of K, D, E and Ztogether with the carbon atoms of the aryl ring to which they areattached form a phenyl ring, then the phenyl ring is optionallysubstituted with one or more substituents selected from aryl, loweralkyl (which alkyl group may itself be optionally substituted orterminated as defined below), Het, halo, cyano, nitro, OR¹⁹, OC(O)R²⁰,C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁵R²⁶, SR²⁷, C(O)SR²⁷ or C(S)NR²⁵R²⁶wherein R¹⁹ to R²⁷ each independently represent hydrogen or lower alkyl(which alkyl group may itself be optionally substituted or terminated asdefined herein). More preferably, the phenyl ring is not substituted byany substituents i.e. it bears hydrogen atoms only.

Preferred compounds of formula I include those wherein:

A and B each independently represent unsubstituted C₁ to C₆ alkylene;

K, D, Z and E each independently represent hydrogen, C₁-C₆ alkyl,phenyl, C₁-C₆ alkylphenyl or -J-Q³(CR¹³(R¹⁴)(R¹⁵))CR¹⁶(R¹⁷)(R¹⁸) where Jrepresents unsubstituted C₁ to C₆ alkylene; or two of K, D, Z and Etogether with the carbon atoms of the aryl ring to which they areattached form a phenyl ring which is optionally substituted by one ormore substituents selected from lower alkyl, phenyl or loweralkylphenyl.R¹ to R¹⁸ each independently represent C₁ to C₆ alkyl, phenyl or C₁ toC₆ alkylphenyl.

Further preferred compounds of formula I include those wherein:

A and B both represent —CH₂— or C₂H₄, particularly CH₂;

K, D, Z and E each independently represent hydrogen, C₁-C₆ alkyl phenylor C₁-C₆ alkyl or -J-Q³(CR¹³(R¹⁴)(R¹⁵))CR¹⁶(R¹⁷)(R¹⁸) where J is thesame as A; or two of K, D, E and Z together with the carbon atoms of thearyl ring to which they are attached form an unsubstituted phenyl ring;R¹ to R¹⁸ each independently represent C₁ to C₆ alkyl;

Still further preferred compounds of formula I include those wherein:

R¹ to R¹⁸ are the same and each represents C₁ to C₆ alkyl, particularlymethyl.

Still further preferred compounds of formula I include those wherein:

K, D, Z and E are each independently selected from the group consistingof hydrogen or C₁ to C₆ alkyl, particularly where each of K, D, Z and Erepresent the same group, especially where each of K, D, Z and Erepresent hydrogen; or

K represents —CH₂-Q³(CR¹³(R¹⁴)(R¹⁵))CR¹⁶(R¹⁷)(R¹⁸) and D, Z and E areeach independently selected from the group consisting of hydrogen or C₁to C₆ alkyl, particularly where both D and E represent the same group,especially where D, Z and E represent hydrogen.

Especially preferred specific compounds of formula I include thosewherein:

each R¹ to R¹² is the same and represents methyl;

A and B are the same and represent —CH₂—;

K, D, Z and E are the same and represent hydrogen.

In a still further embodiment, at least one (CR^(x)R^(y)R^(z)) groupattached to Q¹ and/or Q², i.e. CR¹R²R³, CR⁴R⁵R⁶, CR⁷R⁸R⁹, or CR¹⁰R¹¹R¹²,may instead be represented by the group (Ad) wherein:

Ad each independently represent an optionally substituted adamantyl orcongressyl radical bonded to the phosphorous atom via any one of itstertiary carbon atoms, the said optional substitution being by one ormore substituents selected from hydrogen, lower alkyl, halo, cyano,nitro, OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁵ R²⁶,C(S)R²⁵R²⁶, SR²⁷ or C(O)SR²⁷; or if both (CR^(x)R^(y)R^(z)) groupsattached to either or both Q¹ and/or Q², or Q³ (if present) togetherwith either Q¹ or Q² (or Q³) as appropriate, form an optionallysubstituted 2-phospha-tricyclo[3.3.1.1{3,7}]decyl group or derivativethereof, or form a ring system of formula

whereinR⁴⁹, and R⁵⁴, each independently represent hydrogen, lower alkyl oraryl;R⁵⁰ to R⁵³, when present, each independently represent hydrogen, loweralkyl, aryl or Het; andY represents oxygen, sulfur or N—R⁵⁵; and R⁵⁵, when present, representshydrogen, lower alkyl or aryl.

In this embodiment, formula I may be represented as:(Ad)_(S)(CR⁷R⁸R⁹)_(T)Q²-A-(K,D)Ar(E,Z)—B-Q¹(Ad)_(u)(CR¹R²R³)_(v)wherein Ar, A, B, K, D, E and Z, Q¹, Q², and Q³, and R¹ to R²⁷ are asdefined hereinbefore except that K, D, E and Z may represent-J-Q³(Ad)_(w)(CR¹³(R¹⁴)(R¹⁵)_(x) instead of-J-Q³(CR¹³(R¹⁴)(R¹⁵))CR¹⁶(R¹⁷)(R¹⁸) and Ad is as defined above,S & U=0, 1 or 2 provided that S+U≧1;T & V=0, 1 or 2 provided that T+V≦3;W & X=0, 1 or 2.

In addition to the preferred embodiments for R¹ to R¹⁸, Q¹ to Q³, A, B,J (when present), K, D, E or Z, R¹⁹ to R²⁷, noted hereinbefore, all ofwhich equally apply to the present embodiment where at least one (Ad)group is present, the following also applies.

Further preferred compounds of formula I include those wherein:

A and B both represent —CH₂— or —C₂H₄—, particularly —CH₂—;

K, D, Z and E each independently represent hydrogen, C₁-C₆ alkyl phenylor C₁-C₆ alkyl or -J-Q³(Ad)_(w)(CR¹³(R¹⁴)(R¹⁵))_(x) where J is the sameas A; or two of K, D, E and Z together with the carbon atoms of the arylring to which they are attached form an unsubstituted phenyl ring;R¹ to R³, R⁷ to R⁹, and R¹³ to R¹⁵ (when present) each independentlyrepresent C₁ to C₆ alkyl, and the total number of (Ad) groups attachedto Q¹ and Q² is ≧3, i.e. S+U≧3, and W and X=0, 1 or 2.

Still further preferred compounds of formula I include those wherein:

R¹ to R³, R⁷ to R⁹ and R¹³ to R¹⁵ (when present) are the same and eachrepresents C₁ to C₆ alkyl, particularly methyl, and the total number of(Ad) groups attached to Q¹ and Q² is ≧3, i.e. S+U≧3.

Still further preferred compounds of formula I include those wherein:

K, D, Z and E are each independently selected from the group consistingof hydrogen or C₁ to C₆ alkyl, particularly where each of K, D, Z and Erepresent the same group, especially where each of K, D, Z and Erepresent hydrogen; or

K represents —CH₂-Q³(Ad)_(w)(CR¹³(R¹⁴)(R¹⁵)_(x) and D, Z and E are eachindependently selected from the group consisting of hydrogen or C₁ to C₆alkyl, particularly where both D and E represent the same group,especially where D, Z and E represent hydrogen, wherein W and X=0, 1 or2.

Especially preferred specific compounds of formula I include thosewherein:

each R¹ to R³, and R⁷ to R⁹ is the same and represents methyl or thetotal number of (Ad) groups attached to Q¹ and Q² is 2, i.e. S+U=2;

A and B are the same and represent —CH₂—;

K, D, Z and E are the same and represent hydrogen.

Especially preferred specific compounds of formula I include thosewherein Ad is joined to Q₁ or Q² at the same position in each case.Preferably S≧1 and U≧1, more preferably, S=2 and U≧1 or vice versa, mostpreferably S & U=2, wherein S is the number of (Ad) groups attached toQ² and U is the number of (Ad) groups attached to Q¹.

Specific but non-limiting examples of bidentate ligands within thisembodiment include the following: 1,2bis(diadamantylphosphinomethyl)benzene, 1,2bis(di-3,5-dimethyladamantylphosphinomethyl)benzene, 1,2bis(di-5-tert-butyladamantaylphosphinomethyl)benzene, 1,2bis(l-adamantyl tert-butyl-phosphinomethyl)benzene, 1,2bis(di-1-diamantanephosphinomethyl)benzene,1-[(diadamantylphosphinomethyl)-2-(di-tert-butylphosphinomethyl)]benzene,1-(di-tert-butylphosphinomethyl)-2-(dicongressylphosphinomethyl)benzene,1-(di-tert-butylphosphinomethyl)-2-(phospha-adamantylphosphinomethyl)benzene,1-(diadamantylphosphinomethyl)-2-(phospha-adamantylphosphinomethyl)benzene,1-(tert-butyladamantyl)-2-(di-adamantyl)-(phosphinomethyl)benzene and1-[(P-(2,2,6,6,-tetra-methylphosphinan-4-one)phosphinomethyl)]-2-(phospha-adamantylphosphinomethyl)benzene.

Nevertheless, the skilled person in the art would appreciate that otherbidentate ligands can be envisaged without departing from the scope ofthe invention.

In a yet further embodiment, the bidentate phosphine ligand is ofgeneral formula (III).

wherein:

A₁ and A₂, and A₃, A₄ and A₅ (when present), each independentlyrepresent lower alkylene;K¹ is selected from the group consisting of hydrogen, lower alkyl, aryl,Het, halo, cyano, nitro, —OR¹⁹, —OC(O)R²⁰, —C(O)R²¹, —C(O)OR²²,—N(R²³)R²⁴, —C(O)N(R²⁵)R²⁶, —C(S)(R²⁷)R²⁸, —SR²⁹, —C(O)SR³⁰, —CF₃ or-A₃-Q³(X⁵)X⁶;D¹ is selected from the group consisting of hydrogen, lower alkyl, aryl,Het, halo, cyano, nitro, —OR¹⁹, OC(O)R²⁰, —C(O)R²¹, —C(O)OR²²,—N(R²³)R²⁴, —C(O)N(R²⁵)R²⁶, —C(S)(R²⁷)R²⁸, —SR²⁹, —C(O)SR³⁰, —CF₃ or-A₄-Q⁴(X⁷)X⁸;E¹ is selected from the group consisting of hydrogen, lower alkyl, aryl,Het, halo, cyano, nitro, —OR¹⁹, —OC(O)R²⁰, —C(O)R²¹, —C(O)OR²²,—N(R²³)R²⁴, —C(O)N(R²⁵)R²⁶, —C(S)(R²⁷)R²⁸, —SR²⁹, —C(O)SR³⁰, —CF₃ or-A₅-Q⁵(X⁹)X¹⁰;or both D¹ and E¹ together with the carbon atoms of the cyclopentadienylring to which they are attached form an optionally substituted phenylring:X¹ represents CR¹(R²)(R³), congressyl or adamantyl, X² representsCR⁴(R⁵)(R⁶), congressyl or adamantyl, or X¹ and X² together with Q² towhich they are attached form an optionally substituted2-phospha-tricyclo[3.3.1.1{3,7}]decyl group or derivative thereof, or X¹and X² together with Q² to which they are attached form a ring system offormula IIIa

X³ represents CR⁷(R⁸)(R⁹), congressyl or adamantyl, X⁴ representsCR¹⁰(R¹¹)(R¹²), congressyl or adamantyl, or X³ and X⁴ together with Q¹to which they are attached form an optionally substituted2-phospha-tricyclo[3.3.1.1{3,7}]decyl group or derivative thereof, or X³and X⁴ together with Q¹ to which they are attached form a ring system offormula IIIb

X⁵ represents CR¹³(R¹⁴)(R¹⁵), congressyl or adamantyl, X⁶ representsCR¹⁶(R¹⁷)(R¹⁸), congressyl or adamantyl, or X⁵ and X⁶ together with Q³to which they are attached form an optionally substituted2-phospha-tricyclo[3.3.1.1{3,7}]decyl group or derivative thereof, or X⁵and X⁶ together with Q³ to which they are attached form a ring system offormula IIIc

X⁷ represents CR³¹(R³²)(R³³), congressyl or adamantyl, X⁸ representsCR³⁴(R³⁵)(R³⁶), congressyl or adamantyl, or X⁷ and X⁸ together with Q⁴to which they are attached form an optionally substituted2-phospha-tricyclo[3.3.1.1{3,7}]decyl group or derivative thereof, or X⁷and X⁸ together with Q⁴ to which they are attached form a ring system offormula Hid

X⁹ represents CR³⁷ (R³⁸)(R³⁹), congressyl or adamantyl, X¹⁰ representsCR⁴⁰(R⁴¹)(R⁴²), congressyl or adamantyl, or X⁹ and X¹⁰ together with Q⁵to which they are attached form an optionally substituted2-phospha-tricyclo[3.3.1.1.{3,7}]decyl group or derivative thereof, orX⁹ and X¹⁰ together with Q⁵ to which they are attached form a ringsystem of formula Hie

and in this yet further embodiment,Q¹ and Q², and Q³, Q⁴ and Q⁵ (when present), each independentlyrepresent phosphorus, arsenic or antimony;M represents a Group VIB or VIIIB metal or metal cation thereof;L₁ represents an optionally substituted cyclopentadienyl, indenyl oraryl group;L₂ represents one or more ligands each of which are independentlyselected from hydrogen, lower alkyl, alkylaryl, halo, CO, P(R⁴³)(R⁴⁴)R⁴⁵or N(R⁴⁶)(R⁴⁷)R⁴⁸;R¹ to R¹⁸ and R³¹ to R⁴², when present, each independently representhydrogen, lower alkyl, aryl, halo or Het;R¹⁹ to R³⁰ and R⁴³ to R⁴⁸, when present, each independently representhydrogen, lower alkyl, aryl or Het;R⁴⁹, R⁵⁴ and R⁵⁵, when present, each independently represent hydrogen,lower alkyl or aryl;R⁵⁰ to R⁵³, when present, each independently represent hydrogen, loweralkyl, aryl or Het;Y¹, Y², Y³, Y⁴ and Y⁵, when present, each independently representoxygen, sulfur or N—R⁵⁵;n=0 or 1;and m=0 to 5;provided that when n=1 then m equals 0, and when n equals 0 then m doesnot equal 0.

Preferably in a compound of formula III when both K¹ represents-A₃-Q³(X⁵)X⁶ and E¹ represents -A₅-Q⁵(X⁹)X¹⁰, then D¹ represents-A₄-Q⁴(X⁷)X⁸.

Preferably, in this embodiment, R¹ to R¹⁸ and R³¹ to R⁴², when present,each independently represent hydrogen, optionally substituted C₁ to C₆alkyl, C₁-C₆ alkyl phenyl (wherein the phenyl group is optionallysubstituted as defined herein), trifluoromethyl or phenyl (wherein thephenyl group is optionally substituted as defined herein). Even morepreferably, R¹ to R¹⁸ and R³¹ to R⁴², when present, each independentlyrepresent hydrogen, C₁ to C₆ alkyl, which is optionally substituted asdefined herein, trifluoromethyl or optionally substituted phenyl. Evenmore preferably, R¹ to R¹⁸ and R³¹ to R⁴², when present eachindependently represent hydrogen, non-substituted C₁ to C₆ alkyl orphenyl which is optionally substituted with one or more substituentsselected from non-substituted C₁ to C₆ alkyl or OR¹⁹ where R¹⁹represents hydrogen or unsubstituted C₁ to C₆ alkyl. More preferably, R¹to R¹⁸ and R³¹ to R⁴², when present, each independently representhydrogen or non-substituted C₁ to C₆ alkyl such as methyl, ethyl,n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, pentyl, hexyl andcyclohexyl, especially methyl. Most preferably, R¹ to R¹⁸ and R³¹ to R⁴²when present, each independently represent non-substituted C₁ to C₆alkyl such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl,tert-butyl, pentyl, hexyl and cyclohexyl, especially methyl.

Alternatively, or additionally, one or more of the groups R¹ to R³, R⁴to R⁶, R⁷ to R⁹, R¹⁰ to R¹², R¹³ to R¹⁵, R¹⁶ to R¹⁸, R³¹ to R³³, R³⁴ toR³⁶, R³⁷ to R³⁹ or R⁴⁰ to R⁴² (when present) together with the carbonatom to which they are attached independently may form cyclic alkylstructures such as 1-norbornyl or 1-norbornadienyl.

Alternatively, or additionally, one or more of the groups R¹ and R², R⁴and R⁵, R⁷ and R⁸, R¹⁰ and R¹¹, R¹³ and R¹⁴, R¹⁶ and R¹⁷, R³¹ and R³²,R³⁴ and R³⁵, R³⁷ and R³⁸ or R⁴⁰ and R⁴¹ (when present) together with thecarbon atom to which they are attached independently may form a cyclicalkyl structures, preferably a C₅ to C₇ cyclic alkyl structure such ascyclohexyl and cyclopentyl, and R³, R⁶, R⁹, R¹², R¹⁵, R¹⁸, R³³, R³⁶, R³⁹and R⁴² (when present) each independently represent hydrogen, loweralkyl, trifluoromethyl or aryl as defined above, particularlynon-substituted C₁ to C₆ alkyl and hydrogen, especially non-substitutedC₁ to C₆ alkyl.

In an especially preferred embodiment, each of R¹ to R¹⁸ and R³¹ to R⁴²,when present, do not represent hydrogen. Suitably, such an arrangementmeans Q¹, Q², Q³, Q⁴ and Q⁵ are bonded to a carbon atom of X¹ to X¹⁰,respectively, which bears no hydrogen atoms.

Preferably, R¹, R⁴, R⁷, R¹⁰, R¹³, R¹⁶, R³¹, R³⁴, R³⁷ and R⁴⁰ (whenpresent), each represent the same substituent as defined herein; R², R⁵,R⁸, R¹¹, R¹⁴, R¹⁷, R³², R³⁵, R³⁸ and R⁴¹ (when present), each representthe same substituent as defined herein; and R³, R⁶, R⁹, R¹², R¹⁵, R¹⁸,R³³, R³⁶, R³⁹ and R⁴² (when present), each represent the samesubstituent as defined herein. More preferably R¹, R⁴, R⁷, R¹⁰, R¹³,R¹⁵, R³¹, R³⁴, R³⁷ and R⁴⁰ (when present) each represent the same C₁-C₆alkyl, particularly non-substituted C₁-C₆ alkyl, such as methyl, ethyl,n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, pentyl, hexyl orcyclohexyl, or trifluoromethyl; R², R⁵, R⁸, R¹¹, R¹⁴, R¹⁷, R³², R³⁵, R³⁸and R⁴¹ (when present), each independently represent the same C₁-C₆alkyl as defined above, or trifluoromethyl; and R³, R⁶, R⁹, R¹², R¹⁵,R¹⁸, R³³, R³⁶, R³⁹ and R⁴² (when present), each independently representthe same C₁-C₆ alkyl as defined above, or trifluoromethyl. For example:R¹, R⁴, R⁷, R¹⁰, R¹³ and R¹⁶ (when present) each represent methyl; R²,R⁵, R⁸, R¹¹, R¹⁴ and R¹⁷ each represent ethyl (when present); and, R³,R⁶, R⁹, R¹², R¹⁵ and R¹⁸ (when present) each represent n-butyl orn-pentyl.

In an especially preferred embodiment each R¹ to R¹⁸ and R³¹ to R⁴²group (when present) represents the same substituent as defined herein.Preferably, each R¹ to R¹⁸ and R³¹ to R⁴² group represents the same C₁to C₆ alkyl group, particularly non-substituted C₁-C₆ alkyl, such asmethyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl,pentyl, hexyl and cyclohexyl, or trifluoromethyl. Most preferably, eachR¹ to R¹⁸ and R³¹ to R⁴² group represents non-substituted C₁-C₆ alkyl,particularly methyl.

The term adamantyl when used herein means an adamantyl group which maybe bonded to Q¹, Q², Q³, Q⁴ and Q⁵, respectively, in position 1 or 2.Tricyclo[3.3.1.1.{3,7}]decyl is the systematic name for an adamantylgroup, suitably Q¹, Q², Q³, Q⁴ and Q⁵, respectively, may be bonded tothe 1 position or 2 position of one or two tricyclo[3.3.1.1.{3,7}]decylgroups. Preferably, Q¹ and Q², and Q³, Q⁴ and Q⁵, when present, isbonded to a tertiary carbon of one or more adamantyl groups. Suitably,when the adamantyl group represents unsubstituted adamantyl, Q¹ and Q²,and Q³, Q⁴ and Q⁵ when present are preferably bonded to the 1 positionof one or more tricyclo[3.3.1.1{3,7}]decyl groups i.e. the carbon atomof the adamantyl group bears no hydrogen atom.

The adamantyl group may optionally comprise, besides hydrogen atoms, oneor more substituents selected from lower alkyl, —OR¹⁹, —OC(O)R²⁰, halo,nitro, —C(O)R²¹, —C(O)OR²², cyano, aryl, —N(R²³)R²⁴, —C(O)N(R²⁵)R²⁶,—C(S) (R²⁷)R²⁸, —CF₃, —P(R⁵⁶)R⁵⁷, —PO(R⁵⁸)(R⁵⁹), —PO₃H₂,—PO(OR⁶⁰)(OR⁶¹), or —SO₃R⁶², wherein R¹⁹, R²⁰, R²¹, R²², R²³, R²⁴, R²⁵,R²⁶, R²⁷, R²⁸, lower alkyl, cyano and aryl are as defined herein and R⁵⁶to R⁶² each independently represent hydrogen, lower alkyl, aryl or Het.

Suitably, when the adamantyl group is substituted with one or moresubstituents as defined above, highly preferred substituents includeunsubstituted C₁ to C₆ alkyl, —OR¹⁹, —OC(O)R²⁰, phenyl, —C(O)OR²²,fluoro, —SO₃H, —N(R²³)R²⁴, —P(R⁵⁶)R⁵⁷, —C(O)N(R²⁵)R²⁶ and —PO(R⁵⁸)(R⁵⁹),—CF₃, wherein R¹⁹ represents hydrogen, unsubstituted C₁-C₈ alkyl orphenyl, R²⁰, R²², R²³, R²⁴, R²⁵, R²⁶ each independently representhydrogen or unsubstituted C₁-C₈ alkyl, R⁵⁶ to R⁵³, R⁵⁶ eachindependently represent unsubstituted C₁-C₈ alkyl or phenyl.

Suitably, the adamantyl group may comprise, besides hydrogen atoms, upto 10 substituents as defined above, preferably up to 5 substituents asdefined above, more preferably up to 3 substituents as defined above.Suitably, when the adamantyl group comprises, besides hydrogen atoms,one or more substituents as defined herein, preferably each substituentis identical. Preferred substituents are unsubstituted C₁-C₈ alkyl andtrifluoromethyl, particularly unsubstituted C₁-C₈ alkyl such as methyl.A highly preferred adamantyl group comprises hydrogen atoms only i.e.the adamantyl group is not substituted.

Preferably, when more than one adamantyl group is present in a compoundof formula III, each adamantyl group is identical.

By the term 2-phospha-tricyclo[3.3.1.1.{3,7}]decyl group we mean a2-phospha-adamantyl group formed by the combination of X¹ and X²together with Q² to which they are attached, a 2-phospha-adamantyl groupformed by the combination of X³ and X⁴ together with Q¹ to which theyare attached, a 2-phospha-adamantyl group formed by the combination ofX⁵ and X⁶ together with Q³ to which they are attached, a2-phospha-adamantyl group formed by the combination of X⁷ and X⁸together with Q⁴ to which they are attached and a 2-phospha-adamantylgroup formed by the combination of X⁹ and X¹⁰ together with Q⁵ to whichthey are attached, wherein Q¹, Q², Q³, Q⁴ and Q⁵ is in the 2-position ofthe adamantyl group of which it forms an integral part and each of Q¹,Q², Q³, Q⁴ and Q⁵ represents phosphorus.

The 2-phospha-tricyclo[3.3.1.1.{3,7}]decyl group (referred to as2-phospha-adamantyl group herein) may optionally comprise, besidehydrogen atoms, one or more substituents. Suitable substituents includethose substituents as defined herein in respect of the adamantyl group.Highly preferred substituents include lower alkyl, particularlyunsubstituted C₁-C₈ alkyl, especially methyl, trifluoromethyl, —OR¹⁹wherein R¹⁹ is as defined herein particularly unsubstituted C₁-C₈ alkylor aryl, and 4-dodecylphenyl. When the 2-phospha-adamantyl groupincludes more than one substituent, preferably each substituent isidentical.

Preferably, the 2-phospha-adamantyl group is substituted on one or moreof the 1, 3, 5 or 7 positions with a substituent as defined herein. Morepreferably, the 2-phospha-adamantyl group is substituted on each of the1, 3 and 5 positions. Suitably, such an arrangement means thephosphorous atom of the 2-phospha-adamantyl group is bonded to carbonatoms in the adamantyl skeleton having no hydrogen atoms. Mostpreferably, the 2-phospha-adamantyl group is substituted on each of the1, 3, 5 and 7 positions. When the 2-phospha-adamantyl group includesmore than 1 substituent preferably each substituent is identical.Especially preferred substituents are unsubstituted C₁-C₈ alkyl andtrifluoromethyl, particularly unsubstituted C₁-C₈ alkyl such as methyl.

Preferably, the 2-phospha-adamantyl group includes additionalheteroatoms, other than the 2-phosphorous atom, in the2-phospha-adamantyl skeleton. Suitable additional heteroatoms includeoxygen and sulphur atoms, especially oxygen atoms. More preferably, the2-phospha-adamantyl group includes one or more additional heteroatoms inthe 6, 9 and 10 positions. Even more preferably, the 2-phospha-adamantylgroup includes an additional heteroatom in each of the 6, 9 and 10positions. Most preferably, when the 2-phospha-adamantyl group includestwo or more additional heteroatoms in the 2-phospha-adamantyl skeleton,each of the additional heteroatoms are identical. An especiallypreferred 2-phospha-adamantyl group, which may optionally be substitutedwith one or more substituents as defined herein, includes an oxygen atomin each of the 6, 9 and 10 positions of the 2-phospha-adamantylskeleton.

Highly preferred 2-phospha-adamantyl groups as defined herein include2-phospha-1,3,5,7-tetramethyl-6,9,10-trioxadamantyl group,2-phospha-1,3,5-trimethyl-6,9,10-trioxadamantyl group,2-phospha-1,3,5,7-tetra(trifluoromethyl)-6,9,10-trioxadamantyl group,and 2-phospha-1,3,5-tri(trifluoromethyl)-6,9,10-trioxadamantyl group.Most preferably, the 2-phospha-adamantyl is selected from2-phospha-1,3,5,7-tetramethyl-6,9,10-trioxadamantyl group or2-phospa-1,3,5,-trimethyl-6,9,10-trioxadamantyl group.

Preferably, when more than one 2-phospha-adamantyl group is present in acompound of formula III, each 2-phospha-adamantyl group is identical.

The above definition of the term “2-phospha-tricyclo[3.3.1.1.{3,7}]decylgroup” applies equally to the group when it is present in formula I butwherein X^(n) in formula III, i.e. X¹, X², X³ . . . X¹⁰, is denotedCR^(x)R^(y)R^(z), i.e. CR¹R²R³, . . . CR¹⁶R¹⁷R¹⁸, in formula I.

The term congressyl when used herein means a congressyl group (alsoknown as diamantyl group) which may be bonded to Q¹, Q², Q³, Q⁴ and Q⁵respectively. Preferably, Q¹ and Q², and Q³, Q⁴ and Q⁵, when present,are bonded to one of the tertiary carbon atoms of the congressyl groups.Suitably, when the congressyl group is unsubstituted, Q¹ and Q², and Q³,Q⁴ and Q⁵ when present, are preferably bonded to the 1-position of oneor more congressyl groups.

The congressyl group may optionally comprise, beside hydrogen atoms, oneor more substituents. Suitable substituents include those substituentsas defined herein in respect of the adamantyl group. Highly preferredsubstituents include unsubstituted C₁-C₆ alkyl groups, particularlymethyl, and trifluoromethyl. Most preferably, the congressyl group isunsubstituted and comprises hydrogen atoms only.

Preferably, when more than one congressyl group is present in a compoundof formula III, each congressyl group is identical.

Preferably, where one or more ring systems of formula IIIa, IIIb, IIIc,IIId or IIIe are present in a compound of formula III, R⁵⁰ to R⁵³ eachindependently represent lower alkyl, aryl or Het, which groups areoptionally substituted and/or terminated as defined herein. Such anarrangement means Q², Q¹, Q³, Q⁴ and Q⁵ of the ring system of formulaIIIa to IIIe, respectively, is not bonded to a carbon atom bearing ahydrogen atom. Even more preferably, R⁵⁰ to R⁵³ each independentlyrepresent optionally substituted C₁-C₆ alkyl, preferably non-substitutedC₁-C₆ alkyl, phenyl optionally substituted with non-substituted C₁-C₆alkyl or OR¹⁹ where R¹⁹ represents non-substituted C₁-C₆ alkyl, ortrifluoromethyl. Even more preferably R⁵⁰ to R⁵³ each represent the samegroup as defined herein, particularly non-substituted C₁-C₆ alkyl,especially methyl.

Preferably, where one or more ring system of formula IIIa to IIIe arepresent in a compound of formula III, R⁴⁹ and R⁵⁴ each independentlyrepresent optionally substituted C₁-C₆ alkyl, preferably non-substitutedC₁-C₆ alkyl, phenyl optionally substituted with non-substituted C₁-C₆alkyl or OR¹⁹ where R¹⁹ represents non-substituted C₁-C₆ alkyl,trifluoromethyl or hydrogen. More preferably, R⁴⁹ and R⁵⁴ represent thesame group as defined herein, especially hydrogen.

Preferably, where one or more ring systems of formula IIIa to IIIe arepresent in a compound of formula III, Y¹ to Y⁵ are identical. Mostpreferably, each of Y¹ to Y⁵ represents oxygen. Preferably, where morethan one ring system of formula IIIa to IIIe is present in a compound offormula III, each such ring system is identical.

Preferred embodiments of the present invention include those wherein:

X¹ represents CR¹(R²)(R³), X² represents CR⁴(R⁵)(R⁶), X³ representsCR⁷(R⁸)(R⁹) and X⁴ represents CR¹⁰(R¹¹)(R¹²);

X¹ represents CR¹(R²)(R³), X² represents adamantyl, X³ representsCR⁷(R⁸)(R⁹) and X⁴ represents adamantyl;

X¹ represents CR¹(R²)(R³), X² represents congressyl, X³ representsCR⁷(R⁸)(R⁹) and X⁴ represents congressyl;

X¹ represents CR¹(R²)(R³), X² represents CR⁴(R⁵)(R⁶), and X³ and X⁴together with Q¹ to which they are attached form a ring system offormula IIIb or a 2-phospha-adamantyl group;

X¹ represents CR¹(R²)(R³), X² represents adamantyl, X³ and X⁴ togetherwith Q¹ to which they are attached form a ring system of formula IIIb ora 2-phospha-adamantyl group;

X¹ represents CR¹(R²)(R³), X² represents congressyl, X³ and X⁴ togetherwith Q¹ to which they are attached form a ring system of formula IIIb ora 2-phospha-adamantyl group;

X¹ to X⁴ each independently represent adamantyl;

X¹ to X⁴ each independently represent congressyl;

X¹ and X² each independently represent adamantyl and X³ and X⁴ eachindependently represent congressyl;

X¹ and X³ independently represent adamantyl and X² and X⁴ independentlyrepresent congressyl;

X¹ and X² independently represent adamantyl, X³ represents CR⁷(R⁸)(R⁹)and X⁴ represents CR¹⁰(R¹¹)(R¹²);

X¹ and X² independently represent congressyl, X³ represents CR⁷(R⁸)(R⁹)and X⁴ represents CR¹⁰(R¹¹)(R¹²);

X¹ and X² independently represent adamantyl, and X³ and X⁴ together withQ¹ to which they are attached form a ring system of formula IIIb or a2-phospha-adamantyl group;

X¹ and X² independently represent congressyl, and X³ and X⁴ togetherwith Q¹ to which they are attached form a ring system of formula IIIb ora 2-phospha-adamantyl group;

X¹ and X² together with Q² to which they are attached form a ring systemof formula IIIa, and X³ and X⁴ together with Q¹ to which they areattached form a ring system of formula IIIb;

X¹ and X² together with Q² to which they are attached form a2-phospha-adamantyl group, and X³ and X⁴ together with Q¹ to which theyare attached form a 2-phospha-adamantyl group;

Highly preferred embodiments of the present invention include thosewherein:

X¹ represents CR¹(R²)(R³), X² represents CR⁴(R⁵)(R⁶), X³ representsCR⁷(R⁸)(R⁹) and X⁴ represents CR¹⁰(R¹¹)(R¹²);

X¹ represents CR¹(R²)(R³), X² represents adamantyl, X³ representsCR⁷(R⁸)(R⁹) and X⁴ represents adamantyl;

X¹ represents CR¹(R²)(R³), X² represents congressyl, X³ representsCR⁷(R⁸)(R⁹) and X⁴ represents congressyl;

X¹ to X⁴ each independently represent adamantyl;

X¹ to X⁴ each independently represent congressyl;

X¹ and X² together with Q² to which they are attached form a ring systemof formula IIIa, and X³ and X⁴ together with Q¹ to which they areattached form a ring system of formula IIIb;

X¹ and X² together with Q² to which they are attached form a2-phospha-adamantyl group, and X³ and X⁴ together with Q¹ to which theyare attached form a 2-phospha-adamantyl group;

Preferably in a compound of formula III, X¹ is identical to X³ and X² isidentical to X⁴. More preferably, X¹ is identical to X³ and X⁵, X⁷ andX⁹ when present, and X² is identical to X⁴ and X⁶, X⁸ and X¹⁰ whenpresent. Even more preferably, X¹ to X⁴ are identical. Most preferably,X¹ to X⁴ are identical to each of X⁶ to X¹⁰ when present.

Preferably, in the compound of formula III, X¹ and X² representidentical substituents, X³ and X⁴ represent identical substituents, X⁵and X⁶ (when present) represent identical substituents, X⁷ and X⁸ (whenpresent) represent identical substituents, and X⁹ and X¹⁰ (when present)represent identical substituents.

Preferably, in a compound of formula III, K¹ represents -A₃-Q³(X⁵)X⁶,hydrogen, lower alkyl, —CF₃, phenyl or lower alkyl phenyl. Morepreferably, K¹ represents -A₃-Q³(X⁵)X⁶, hydrogen, unsubstituted C₁-C₆alkyl, unsubstituted phenyl, trifluoromethyl or C₁-C₆ alkyl phenyl.

In a particular preferred embodiment K¹ in a compound of formula IIIrepresents hydrogen.

In an alternative embodiment where K¹ does not represent hydrogen, K¹represents -A₃-Q³(X⁵)X⁶. Preferably, X⁵ is identical to X³ or X¹, and X⁶is identical to X² or X⁴. More preferably, X⁵ is identical to both X³and X¹, and X⁶ is identical to both X² and X⁴. Even more preferably,-A₃-Q³(X⁵)X⁶ is identical to either -A₁-Q²(X¹)X² or -A₂-Q¹ (X³)X⁴. Mostpreferably, -A₃-Q³(X⁵)X⁶ is identical to both -A₁-Q₂(X¹)X² and -A₂-Q¹(X³)X⁴.

Most preferably, K¹ represents hydrogen in a compound of formula III.

Preferably, in the compound of formula III, D¹ represents -A₄-Q⁴(X⁷)X⁸,hydrogen, lower alkyl, CF₃, phenyl or lower alkylphenyl, and E¹represents -A₅-Q⁵(X⁹)X¹⁰, hydrogen, lower alkyl, CF₃, phenyl or loweralkylphenyl, or D¹ and E¹ together with the carbons of thecyclopentadienyl ring to which they are attached form an optionallysubstituted phenyl ring. More preferably, D¹ represents -A₄-Q⁴(X⁷)X⁸,hydrogen, phenyl, C₁-C₆ alkylphenyl, unsubstituted C₁-C₆ alkyl, such asmethyl, ethyl, propyl, butyl, pentyl and hexyl, or CF₃; E¹ represents-A₅-Q⁵ (X⁹)X¹⁰, hydrogen, phenyl, C₁-C₆ alkylphenyl, unsubstituted C₁-C₆alkyl such as methyl, ethyl, propyl, butyl, pentyl and hexyl, or —CF₃;or both D¹ and E¹ together with the carbon atoms of the cyclopentadienylring to which they are attached form a phenyl ring which is optionallysubstituted with one or more groups selected from phenyl, C₁-C₆alkylphenyl, unsubstituted C₁-C₆ alkyl or —CF₃.

Suitably, when D¹ and E¹ together with the carbon atoms of thecyclopentadienyl ring to which they are attached form an optionallysubstituted phenyl ring, the metal M or cation thereof is attached to anindenyl ring system.

In a particular preferred embodiment, D¹ in a compound of formula III,represents hydrogen.

In an alternative embodiment where D¹ does not represent hydrogen, D¹represents -A₄-Q⁴(X⁷)X⁸. Preferably X⁸ is identical to X⁴ or X², and X⁷is identical to X¹ or X³. More preferably, X⁸ is identical to both X⁴and X², and X⁷ is identical to X¹ and X³. Even more preferably,-A₄-Q⁴(X⁷)X⁸ is identical to either -A₁-Q² (X¹)X² or -A₂-Q¹ (X³)X⁴. Mostpreferably, -A₄-Q⁴(X⁷)X⁸ is identical to both -A₂-Q¹(X³)X⁴, and-A₃-Q³(X⁵)X⁶ if present.

In a particular preferred embodiment, E¹ in a compound of formula IIIrepresents hydrogen.

In an alternative embodiment where E¹ does not represent hydrogen, E¹represents -A₅-Q⁵ (X⁹)X¹⁰. Preferably X¹⁰ is identical to X⁴ or X², andX⁹ is identical to X¹ or X³. More preferably, X¹⁰ is identical to bothX⁴ and X², and X⁹ is identical to X¹ and X³. Even more preferably,-A₅-Q⁵(X⁹)X¹⁰ is identical to either -A₁-Q²(X¹)X² or -A₂-Q¹ (X³)X⁴. Mostpreferably, -A₅-Q⁵ (X⁹)X¹⁰ is identical to both -A₁-Q₂(X¹)X² and -A₂-Q¹(X³)X⁴, and -A₃-Q³(X⁵)X⁶ and -A₄-Q⁴(X⁷)X⁸ if present.

Preferably, in the compound of formula III, when D¹ and E¹ together withthe carbon atoms of the cyclopentadienyl ring to which they are attacheddo not form an optionally substituted phenyl ring, each of K¹, D¹ and E¹represent an identical substituent.

In an alternative preferred embodiment, D¹ and E¹ together with thecarbons of the cyclopentadienyl ring to which they are attached form anunsubstituted phenyl ring.

Highly preferred embodiments of compounds of formula III include thosewherein:

K¹, D¹ and E¹ are identical substituents as defined herein, particularlywhere K¹, D¹ and E¹ represent hydrogen;

K¹ represents hydrogen, and D¹ and E¹ together with the carbons of thecyclopentadienyl ring to which they are attached form an unsubstitutedphenyl ring;

K¹ represents -A₃-Q³(X⁵)X⁶ as defined herein and both D¹ and E¹represent H;

K¹ represents -A₃-Q³(X⁵)X⁶ as defined herein and D¹ and E¹ together withthe carbon atoms of the cyclopentadienyl ring to which they are attachedform an unsubstituted phenyl ring;

K¹ represents -A₃-Q³(X⁵)X⁶, D¹ represents -A₄-Q⁴(X⁷)X⁸ and E¹ represents-A₅-Q⁵ (X⁹)X¹⁰.

Especially preferred compounds of formula III include those where bothD¹ and E¹ represent hydrogen or D¹ and E¹ together with the carbon atomsof the cyclopentadienyl ring to which they are attached form anunsubstituted phenyl ring, particularly those compounds where both D¹and E¹ represent hydrogen.

Preferably, in the compound of formula III, A₁ and A₂, and A₃, A₄ and A₅(when present), each independently represent C₁ to C₆ alkylene which isoptionally substituted as defined herein, for example with lower alkylgroups. Suitably, A₁ and A₂, and A₃, A₄ and A₅ (when present) mayinclude a chiral carbon atom. Preferably, the lower alkylene groupswhich A₁ to A₅ may represent are non-substituted. A particular preferredlower alkylene, which A₁ to A₅ may independently represent, is —CH₂— or—C₂H₄—. Most preferably, each of A₁ and A₂, and A₃, A₄ and A₅ (whenpresent), represent the same lower alkylene as defined herein,particularly —CH₂—.

In the compound of formula III, preferably each Q¹ and Q², and Q³, Q⁴and Q⁵ (when present) are the same. Most preferably, each Q¹ and Q², andQ³, Q⁴ and Q⁵ (when present), represents phosphorus.

It will be appreciated by those skilled in the art that the compounds offormula III may function as ligands that coordinate with the Group VIBor Group VIIIB metal or compound thereof in the formation of thecatalyst system of the invention. Typically, the Group VIB or GroupVIIIB metal or compound thereof coordinates to the one or morephosphorus, arsenic and/or antimony atoms of the compound of formulaIII. It will be appreciated that the compounds of formula III may bereferred to broadly as “metallocenes”.

Suitably, when n=1 and L₁ represents an optionally substitutedcyclopentadienyl or indenyl group, the compounds of formula III maycontain either two cyclopentadienyl rings, two indenyl rings or oneindenyl and one cyclopentadienyl ring (each of which ring systems mayoptionally be substituted as described herein). Such compounds may bereferred to as “sandwich compounds” as the metal M or metal cationthereof is sandwiched by the two ring systems. The respectivecyclopentadienyl and/or indenyl ring systems may be substantiallycoplanar with respect to each other or they may be tilted with respectto each other (commonly referred to as bent metallocenes).

Alternatively, when n=1 and L₁ represents aryl, the compounds of theinvention may contain either one cyclopentadienyl or one indenyl ring(each of which ring systems may optionally be substituted as describedherein) and one aryl ring which is optionally substituted as definedherein. Suitably, when n=1 and L₁ represents aryl then the metal M ofthe compounds of formula III as defined herein is typically in the formof the metal cation.

In a particularly preferred embodiment of the present invention, in acompound of formula III, n=1, L₁ is as defined herein and m=0.

Preferably, when n=1 in the compound of formula III, L₁ representscyclopentadienyl, indenyl or aryl ring each of which rings areoptionally substituted by one or more substituents selected fromhydrogen, lower alkyl, halo, cyano, nitro, —OR¹⁹, —OC(O)R²⁰, —C(O)R²¹,—C(O)OR²², —N(R²³)R²⁴, —C(O)N(R²⁵)R²⁶, —C(S)(R²⁷)R²⁸—SR²⁹, —C(O)SR³⁰,—CF₃ or ferrocenyl (by which we mean the cyclopentadienyl, indenyl oraryl ring which L₁ may represent is bonded directly to thecyclopentadienyl ring of the ferrocenyl group), wherein R¹⁹ to R³⁰ is asdefined herein. More preferably, if the cyclopentadienyl, indenyl oraryl ring which L₁ may represent is substituted it is preferablysubstituted with one or more substituents selected from unsubstitutedC₁-C₆ alkyl, halo, cyano, —OR¹⁹, —OC(O)R²⁰, —C(O)R²¹, —C(O)OR²²,—N(R²³)R²⁴ where R¹⁹, R²⁰, R²¹, R²², R²³ and R²⁴ each independentlyrepresent hydrogen or C₁-C₆ alkyl. Even more preferably, if thecyclopentadienyl, indenyl or aryl ring which L₁ may represent issubstituted, it is preferably substituted with one or more substituentsselected from unsubstituted C₁-C₆ alkyl.

Preferably, when n=1, L₁ represents cyclopentadienyl, indenyl, phenyl ornapthyl optionally substituted as defined herein. Preferably, thecyclopentadienyl, indenyl, phenyl or napthyl groups are unsubstituted.More preferably, L₁ represents cyclopentadienyl, indenyl or phenyl, eachof which rings are unsubstituted. Most preferably, L₁ representsunsubstituted cyclopentadienyl.

Alternatively, when n=0, the compounds of the invention contain only onecyclopentadienyl or indenyl ring (each of which ring systems mayoptionally be substituted as described herein). Such compounds may bereferred to as “half sandwich compounds”. Preferably, when n=0 then mrepresents 1 to 5 so that the metal M of the compounds of formula IIIhas an 18 electron count. In other words, when metal M of the compoundsof formula III is iron, the total number of electrons contributed by theligands L₂ is typically five.

In a particularly preferred alternative embodiment of the presentinvention, in a compound of formula III, n=0, L₂ is as defined hereinand m=3 or 4, particularly 3.

Preferably, when n is equal to zero and m is not equal to zero in acompound of formula III, L₂ represents one or more ligands each of whichare independently selected from lower alkyl, halo, —CO, —P(R⁴³)(R⁴⁴)R⁴⁵or —N(R⁴⁶)(R⁴⁷)R⁴⁸.

More preferably, L₂ represents one or more ligands each of which areindependently selected from unsubstituted C₁ to C₄ alkyl, halo,particularly chloro, —CO, —P (R⁴³)(R⁴⁴)R⁴⁵ or —N(R⁴⁶)(R⁴⁷)R⁴⁸, whereinR⁴³ to R⁴⁸ are independently selected from hydrogen, unsubstituted C₁ toC₆ alkyl or aryl, such as phenyl.

Suitably, the metal M or metal cation thereof in the compounds offormula III is typically bonded to the cyclopentadienyl ring(s), thecyclopentadienyl moiety of the indenyl ring(s) if present, the aryl ringif present, and/or the ligands L₂ if present. Typically, thecyclopentadienyl ring or the cyclopentadienyl moiety of the indenyl ringexhibits a pentahapto bonding mode with the metal; however other bondingmodes between the cyclopentadienyl ring or cyclopentadienyl moiety ofthe indenyl ring and the metal, such as trihapto coordination, are alsoembraced by the scope of the present invention.

Most preferably, in a compound of formula III, n=1, m=0 and L₁ isdefined herein, particularly unsubstituted cyclopentadienyl.

Preferably M represents a Group VIB or VIIIB metal. In other words thetotal electron count for the metal M is 18.

Preferably, in the compound of formula III, M represents Cr, Mo, Fe, Coor Ru, or a metal cation thereof. Even more preferably, M represents Cr,Fe, Co or Ru or a metal cation thereof. Most preferably, M is selectedfrom a Group VIIIB metal or metal cation thereof. An especiallypreferred Group VIIIB metal is Fe. Although the metal M as definedherein may be in a cationic form, preferably it carries essentially noresidual charge due to coordination with L₁ and/or L₂ as defined herein.

Especially preferred compounds of formula III include those wherein:

-   (1) X¹ represents CR¹(R²)(R³), X² represents CR⁴ (R⁵)(R⁶), X³    represents CR⁷(R⁸)(R⁹), X⁴ represents CR¹⁰(R¹¹)(R¹²), wherein each    of R¹ to R¹² independently represents unsubstituted C₁-C₆ alkyl or    trifluoromethyl, particularly where each of R¹ to R¹² is identical,    especially where each of R¹ to R¹² represents unsubstituted C₁-C₆    alkyl, particularly methyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   K¹, D¹ and E¹ are the same and represent hydrogen or        unsubstituted C₁-C₆ alkyl, particularly hydrogen;    -   Q¹ and Q² both represent phosphorus;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (2) X¹ represents CR¹(R²)(R³), X² represents CR⁴(R⁵)(R⁶), X³    represents CR⁷(R⁸)(R⁹), X⁴ represents CR¹⁰(R¹¹)(R¹²);    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ represents CR¹³(R¹⁴)(R¹⁵)        and X⁶ represents CR¹⁶(R¹⁷)(R¹⁸);    -   each of R¹ to R¹⁸ independently represent unsubstituted C₁-C₆        alkyl or trifluoromethyl, particularly where each of R¹ to R¹⁸        is identical, especially where each of R¹ to R¹⁸ represents        unsubstituted C₁-C₆ alkyl, particularly methyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q³ each represent phosphorus;    -   D¹ and E¹ are the same and represent hydrogen or unsubstituted        C₁-C₆ alkyl, particularly hydrogen;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (3) X¹ represents CR¹(R²)(R³), X² represents CR⁴(R⁵)(R⁶), X³    represents CR⁷(R⁸)(R⁹), X⁴ represents CR¹⁰(R¹¹)(R¹²);    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ represents CR¹³(R¹⁴)(R¹⁵)        and X⁵ represents CR¹⁶(R¹⁷)(R¹⁸);    -   each of R¹ to R¹⁸ independently represent unsubstituted C₁-C₆        alkyl or trifluoromethyl, particularly where each of R¹ to R¹⁸        is identical, especially where each of R¹ to R¹⁸ represents        unsubstituted C₁-C₆ alkyl, particularly methyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q³ each represent phosphorus;    -   D¹ and E¹ together with the carbon atoms of the cyclopentadienyl        ring to which they are attached form an unsubstituted phenyl        ring;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (4) X¹ represents CR¹(R²)(R³), X² represents CR⁴(R⁵)(R⁶), X³    represents CR⁷(R⁸)(R⁹), X⁴ represents CR¹⁰(R¹¹)(R¹²), wherein each    of R¹ to R¹² independently represent unsubstituted C₁-C₆ alkyl or    trifluoromethyl, particularly where each of R¹ to R¹² is identical,    especially where each of R¹ to R¹² represents unsubstituted C₁-C₆    alkyl, particularly methyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹ and Q² both represent phosphorus;    -   K¹ represents hydrogen or C₁-C₆ alkyl, particularly hydrogen;    -   D¹ and E¹ together with the carbon atoms of the cyclopentadienyl        ring to which they are attached form an unsubstituted phenyl        ring;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (5) X¹ represents CR¹(R²)(R³), X² represents CR⁴ (R⁵)(R⁶), X³    represents CR⁷(R⁸)(R⁹), X⁴ represents CR¹⁰(R¹¹)(R¹²);    -   E¹ represents —CH₂-Q⁵ (X⁹)X¹⁰ wherein X⁹ represents        CR³⁷(R³⁸)(R³⁹) and X¹⁰ represents CR⁴⁰ (R⁴¹)(R⁴²);    -   each of R¹ to R¹² and R³⁷ to R⁴² independently represent        unsubstituted C₁-C₆ alkyl or trifluoromethyl, particularly where        each of R¹ to R¹² and R³⁷ to R⁴² is identical, especially where        each of R¹ to R¹² and R³⁷ to R⁴² represents unsubstituted C₁-C₆        alkyl, particularly methyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q⁵ each represent phosphorus;    -   D¹ and K¹ are the same and represent hydrogen or unsubstituted        C₁-C₆ alkyl, particularly hydrogen;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (6) X¹ represents CR¹ (R²)(R³), X² represents CR⁴(R⁵)(R⁶), X³    represents CR⁷(R⁸)(R⁹), X⁴ represents CR¹⁰(R¹¹)(R¹²);    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ represents CR¹³(R¹⁴)(R¹⁵)        and X⁶ represents CR¹⁶(R¹⁷)(R¹⁸);    -   D¹ represents —CH₂-Q⁴(X⁷)X⁸ wherein X⁷ represents CR³¹(R³²)(R³³)        and X⁸ represents CR³⁴(R³⁵)(R³⁶);    -   E¹ represents —CH₂-Q⁵ (X⁹)X¹⁰ wherein X⁹ represents        CR³⁷(R³⁸)(R³⁹) and X¹⁰ represents CR⁴⁰(R⁴¹)(R⁴²);    -   each of R¹ to R¹⁸ and R³¹ to R⁴² independently represent        unsubstituted C₁-C₆ alkyl or trifluoromethyl, particularly where        each of R¹ to R¹⁸ and R³¹ to R⁴² is identical, especially where        each of R¹ to R¹⁸ and R³¹ to R⁴² represents unsubstituted C₁-C₆        alkyl, particularly methyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q², Q³, Q⁴ and Q⁵ each represent phosphorus    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (7) X¹, X², X³ and X⁴ independently represent adamantyl, especially    where X¹ to X⁴ represent the same adamantyl group;    -   A₁ and A₂ are the same and represent —CH₂—;    -   K¹, D¹ and E¹ are the same and represent hydrogen or        unsubstituted C₁-C₆ alkyl, particularly hydrogen;    -   Q¹ and Q² both represent phosphorus;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (8) X¹, X², X³ and X⁴ independently represent adamantyl, especially    where X¹ to X⁴ represent the same adamantyl group;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ and X⁶ independently        represent adamantyl, especially where X¹ to X⁶ represent the        same adamantyl group;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q³ each represent phosphorus;    -   D¹ and E¹ are the same and represent hydrogen or unsubstituted        C₁-C₆ alkyl, particularly hydrogen;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (9) X¹, X², X³ and X⁴ independently represent adamantyl, especially    where X¹ to X⁴ represent the same adamantyl group;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ and X⁶ independently        represent adamantyl, especially where X¹ to X⁶ represent the        same adamantyl group;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q³ each represent phosphorus;    -   D¹ and E¹ together with the carbon atoms of the cyclopentadienyl        ring to which they are attached form an unsubstituted phenyl        ring;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (10) X¹, X², X³ and X⁴ independently represent adamantyl, especially    where X¹ to X⁴ represent the same adamantyl group;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹ and Q² both represent phosphorus;    -   K¹ represents hydrogen or unsubstituted C₁-C₆ alkyl,        particularly hydrogen;    -   D¹ and E¹ together with the carbon atoms of the cyclopentadienyl        ring to which they are attached form an unsubstituted phenyl        ring;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (11) X¹, X², X³ and X⁴ independently represent adamantyl;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ and X⁶ independently        represent adamantyl;    -   D¹ represents —CH₂-Q⁴(X⁷)X⁶ wherein X⁷ and X⁸ independently        represents adamantyl;    -   E¹ represents —CH₂-Q⁵ (X⁹)X¹⁰ wherein X⁹ and X¹⁰ independently        represents adamantyl, especially where X¹ to X¹⁰ represent the        same adamantyl group;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q², Q³, Q⁴ and Q⁵ each represent phosphorus;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (12) X¹ and X² together with Q² to which they are attached    represents 2-phospha-adamantyl;    -   X³ and X⁴ together with Q¹ to which they are attached represents        2-phospha-adamantyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   K¹, D¹ and E¹ are the same and represent hydrogen or        unsubstituted C₁-C₆ alkyl, particularly hydrogen;    -   Q¹ and Q² both represent phosphorus;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (13) X¹ and X² together with Q² to which they are attached    represents 2-phospha-adamantyl;    -   X³ and X⁴ together with Q¹ to which they are attached represents        2-phospha-adamantyl;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ and X⁶ together with Q³        to which they are attached represents 2-phospha-adamantyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q³ each represent phosphorus;    -   D¹ and E¹ are the same and represent hydrogen or unsubstituted        C₁-C₆ alkyl, particularly hydrogen;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (14) X¹ and X² together with Q² to which they are attached    represents 2-phospha-adamantyl;    -   X³ and X⁴ together with Q¹ to which they are attached represents        2-phospha-adamantyl;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ and X⁶ together with Q³        to which they are attached represents 2-phospha-adamantyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q³ each represent phosphorus;    -   D¹ and E¹ together with the carbon atoms of the cyclopentadienyl        ring to which they are attached form an unsubstituted phenyl        ring;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (15) X¹ and X² together with Q² to which they are attached    represents 2-phospha-adamantyl;    -   X³ and X⁴ together with Q¹ to which they are attached represents        2-phospha-adamantyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹ and Q² both represent phosphorus;    -   K¹ represents hydrogen or unsubstituted C₁-C₆ alkyl,        particularly hydrogen;    -   D¹ and E¹ together with the carbon atoms of the cyclopentadienyl        ring to which they are attached form an unsubstituted phenyl        ring;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (16) X¹ and X² together with Q² to which they are attached    represents 2-phospha-adamantyl;    -   X³ and X⁴ together with Q¹ to which they are attached represents        2-phospha-adamantyl;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ and X⁶ together with Q³        to which they are attached represents 2-phospha-adamantyl;    -   D¹ represents —CH₂-Q⁴(X⁷)X⁸ wherein X⁷ and X⁸ together with Q⁴        to which they are attached represents 2-phospha-adamantyl;    -   E¹ represents —CH₂-Q⁵ (X⁹)X¹⁰ wherein X⁹ and X¹⁰ together with        Q⁵ to which they are attached represents 2-phospha-adamantyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q², Q³, Q⁴ and Q⁵ each represent phosphorus    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (17) X¹ and X² together with Q² to which they are attached form a    ring system of formula IIIa, X³ and X⁴ together with Q¹ to which    they are attached form a ring system of formula IIIb, wherein Y¹ and    Y² both represent oxygen, R⁵⁰ to R⁵³ are independently selected from    unsubstituted C₁-C₆ alkyl or CF₃, and R⁴⁹ and R⁵⁴ represent    hydrogen;    -   A₁ and A₂ are the same and represent —CH₂—;    -   K¹, D¹ and E¹ are the same and represent hydrogen or        unsubstituted C₁-C₆ alkyl, particularly hydrogen;    -   Q¹ and Q² both represent phosphorus;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl (referred to as puc) and m=0.-   (18) X¹ and X² together with Q² to which they are attached form a    ring system of formula IIIa, X³ and X⁴ together with Q¹ to which    they are attached form a ring system of formula IIIb, wherein Y¹ and    Y² both represent oxygen, R⁵⁰ to R⁵³ are independently selected from    unsubstituted C₁-C₆ alkyl or CF₃, and R⁴⁹ and R⁵⁴ represent    hydrogen;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ and X⁶ together with Q³        to which they are attached form a ring system of formula IIIc,        wherein Y³ represents oxygen, R⁵⁰ to R⁵³ are independently        selected from hydrogen, unsubstituted C₁-C₆ alkyl or CF₃ and R⁴⁹        and R⁵⁴ represent hydrogen;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q³ each represent phosphorus;    -   D¹ and E¹ are the same and represent hydrogen or C₁-C₆ alkyl,        particularly hydrogen;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (19) X¹ and X² together with Q² to which they are attached form a    ring system of formula IIIa, X³ and X⁴ together with Q¹ to which    they are attached form a ring system of formula IIIb, wherein Y¹ and    Y² both represent oxygen, R⁵⁰ to R⁵³ are independently selected from    unsubstituted C₁-C₆ alkyl or CF₃, and R⁴⁹ and R⁵⁴ represent    hydrogen;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ and X⁶ together with Q³        to which they are attached form a ring system of formula IIIc,        wherein Y³ represents oxygen, R⁵⁰ to R⁵³ are independently        selected from unsubstituted C₁-C₆ alkyl or CF₃, and R⁴⁹ and R⁵⁴        represent hydrogen;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q³ each represent phosphorus;    -   D¹ and E¹ together with the carbon atoms of the cyclopentadienyl        ring to which they are attached form an unsubstituted phenyl        ring;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (20) X¹ and X² together with Q² to which they are attached form a    ring system of formula IIIa, X³ and X⁴ together with Q¹ to which    they are attached form a ring system of formula IIIb, wherein Y¹ and    Y² both represent oxygen, R⁵⁰ to R⁵³ are independently selected from    unsubstituted C₁-C₆ alkyl or CF₃, and R⁴⁹ and R⁵⁴ represent    hydrogen;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹ and Q² both represent phosphorus;    -   K¹ represents hydrogen or unsubstituted C₁-C₆ alkyl,        particularly hydrogen;    -   D¹ and E¹ together with the carbon atoms of the cyclopentadienyl        ring to which they are attached form an unsubstituted phenyl        ring;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (21) X¹ and X² together with Q² to which they are attached form a    ring system of formula IIIa, X³ and X⁴ together with Q¹ to which    they are attached form a ring system of formula IIIb, wherein Y¹ and    Y² both represent oxygen, R⁵⁰ to R⁵³ are independently selected from    unsubstituted C₁-C₆ alkyl or CF₃, and R⁴⁹ and R⁵⁴ represent    hydrogen;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ and X⁶ together with Q³        to which they are attached form a ring system of formula IIIc,        wherein Y³ represents oxygen, R⁵⁰ to R⁵³ are independently        selected from unsubstituted C₁-C₆ alkyl or CF₃, and R⁴⁹ and R⁵⁴        represent hydrogen;    -   D¹ represents —CH₂-Q⁴(X⁷)X⁸ wherein X⁷ and X⁸ together with Q⁴        to which they are attached form a ring system of formula IIIc,        wherein Y³ represents oxygen, R⁵⁰ to R⁵³ are independently        selected from unsubstituted C₁-C₆ alkyl or CF₃, and R⁴⁹ and R⁵⁴        represent hydrogen;    -   E¹ represents —CH₂-Q⁵ (X⁹)X¹⁰ wherein X⁹ and X¹⁰ together with        Q⁵ to which they are attached form a ring system of formula Hie,        wherein Y⁵ represents oxygen, and R⁵⁰ to R⁵³ are independently        selected from unsubstituted C₁-C₆ alkyl or CF₃, and R⁴⁹ and R⁵⁴        represent hydrogen;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q², Q³, Q⁴ and Q₅ each represent phosphorus;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl;    -   particularly unsubstituted cyclopentadienyl, and m=0.-   (22) X¹, X², X³ and X⁴ independently represent congressyl,    especially where X¹ to X⁴ represent the same congressyl group;    -   A₁ and A₂ are the same and represent —CH₂—;    -   K¹, D¹ and E¹ are the same and represent hydrogen or        unsubstituted C₁-C₆ alkyl, particularly hydrogen;    -   Q¹ and Q² both represent phosphorus;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (23) X¹, X², X³ and X⁴ independently represent congressyl,    especially where X¹ to X⁴ represent the same congressyl group;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ and X⁶ independently        represent congressyl, especially where X¹ to X⁶ represent the        same congressyl group;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q³ each represent phosphorus;    -   D¹ and E¹ are the same and represent hydrogen or unsubstituted        C₁-C₆ alkyl, particularly hydrogen;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (24) X¹, X², X³ and X⁴ independently represent congressyl,    especially where X¹ to X⁴ represent the same congressyl group;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ and X⁶ independently        represent congressyl, especially where X¹ to X⁵ represent the        same congressyl group;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q³ each represent phosphorus;    -   D¹ and E¹ together with the carbon atoms of the cyclopentadienyl        ring to which they are attached form an unsubstituted phenyl        ring;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (25) X¹, X², X³ and X⁴ independently represent congressyl,    especially where X¹ to X⁴ represent the same congressyl group;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹ and Q² both represent phosphorus;    -   K¹ represents hydrogen or unsubstituted C₁-C₆ alkyl,        particularly hydrogen;    -   D¹ and E¹ together with the carbon atoms of the cyclopentadienyl        ring to which they are attached form an unsubstituted phenyl        ring;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (26) X¹, X², X³ and X⁴ independently represent congressyl;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ and X⁶ independently        represent congressyl;    -   D¹ represents —CH₂-Q⁴(X⁷)X⁸ wherein X⁷ and X⁸ independently        represents congressyl;    -   E¹ represents —CH₂-Q⁵ (X⁹)X¹⁰ wherein X⁹ and X¹⁰ independently        represents congressyl, especially where X¹ to X¹⁰ represent the        same congressyl group;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q², Q³, Q⁴ and Q⁵ each represent phosphorus;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (27) X¹ and X³ independently represent adamantyl, especially where    X¹ and X³ represent the same adamantyl group;    -   X² represents CR⁴(R⁵)(R⁶) and X⁴ represents CR¹⁰(R¹¹)(R¹²)        wherein each of R⁴, R⁵, Re, R¹⁰, R¹¹ and R¹² independently        represent C₁-C₆ alkyl or trifluoromethyl, particularly where        each of R⁴ to R⁶ and R¹⁰ to R¹² is identical, especially where        each of R⁴ to R⁶ and R¹⁰ to R¹² represents unsubstituted C₁-C₆        alkyl, particularly methyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   K¹, D¹ and E¹ are the same and represent hydrogen or        unsubstituted C₁-C₆ alkyl, particularly hydrogen;    -   Q¹ and Q² both represent phosphorus;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (28) X¹ and X³ independently represent adamantyl, especially where    X¹ and X³ represent the same adamantyl group;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ represents adamantyl,        especially where X¹, X³ and X⁵ represent the same adamantyl        group;    -   X² represents CR⁴(R⁵)(R⁶), X⁴ represents CR¹⁰(R¹¹)(R¹²), X⁶        represents CR¹⁶(R¹⁷)(R¹⁸), wherein each of R⁴ to R⁶, R¹⁰ to R¹²        and R¹⁶ to R¹⁸ independently represent unsubstituted C₁-C₆ alkyl        or trifluoromethyl, particularly where each of R⁴ to R⁶, R¹⁰ to        R¹², and R¹⁶ to R¹⁸ is identical, especially where each of R⁴ to        R⁶, R¹⁰ to R¹² and R¹⁶ to R¹⁸ represents unsubstituted C₁-C₆        alkyl, particularly methyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q³ each represent phosphorus;    -   D¹ and E¹ are the same and represent hydrogen or unsubstituted        C₁-C₆ alkyl, particularly hydrogen;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (29) X¹ and X³ independently represent adamantyl, especially where    X¹ and X³ represent the same adamantyl group;    -   K¹ represents —CH₂-Q³(X⁵)X⁶ wherein X⁵ represents adamantyl,        especially where X¹, X³ and X⁵ represent the same adamantyl        group;    -   X² represents CR⁴(R⁵)(R⁶), X⁴ represents CR¹⁰(R¹¹)(R¹²), X⁶        represents CR¹⁶(R¹⁷)(R¹⁸), wherein each of R⁴ to R⁵, R¹⁰ to R¹²        and R¹⁶ to R¹⁸ independently represent unsubstituted C₁-C₆ alkyl        or trifluoromethyl, particularly where each of R⁴ to R⁶, R¹⁰ to        R¹², and R¹⁶ to R¹⁸ is identical, especially where each of R⁴ to        R⁶, R¹⁰ to R¹² and R¹⁶ to R¹⁸ represents unsubstituted C₁-C₆        alkyl, particularly methyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹, Q² and Q³ each represent phosphorus;    -   D¹ and E¹ together with the carbon atoms of the cyclopentadienyl        ring to which they are attached form an unsubstituted phenyl        ring;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.-   (30) X¹ and X³ independently represent adamantyl, especially where    X¹ and X³ represent the same adamantyl group;    -   X² represents CR⁴ (R⁵)(R⁶) and X⁴ represents CR¹⁰(R¹¹)(R¹²)        wherein each of R⁴, R⁵, R⁶, R¹⁰, R¹¹ and R¹² independently        represent C₁-C₆ alkyl or trifluoromethyl, particularly where        each of R⁴ to R⁶ and R¹⁰ to R¹² is identical, especially where        each of R⁴ to R⁶ and R¹⁰ to R¹² represents unsubstituted C₁-C₆        alkyl, particularly methyl;    -   A₁ and A₂ are the same and represent —CH₂—;    -   Q¹ and Q² both represent phosphorus;    -   K¹ represents hydrogen or unsubstituted C₁-C₆ alkyl,        particularly hydrogen;    -   D¹ and E¹ together with the carbon atoms of the cyclopentadienyl        ring to which they are attached form an unsubstituted phenyl        ring;    -   M represents Fe;    -   n=1 and L₁ represents cyclopentadienyl, particularly        unsubstituted cyclopentadienyl, and m=0.

Specific but non-limiting examples of bidentate ligands within thisembodiment include the following:1,2-bis-(dimethylaminomethyl)ferrocene,1,2-bis-(ditertbutylphosphinomethyl)ferrocene,1-hydroxymethyl-2-dimethylaminomethylferrocene,1,2-bis-(ditertbutylphosphinomethyl)ferrocene,1-hydroxymethyl-2,3-bis-(dimethylaminomethyl)ferrocene,1,2,3-tris-(ditertbutylphosphinomethyl)ferrocene,1,2-bis-(dicyclohexylphosphinomethyl)ferrocene,1,2-bis-(di-iso-butylphosphinomethyl)ferrocene,1,2-bis-(dicyclopentylphosphinomethyl)ferrocene,1,2-bis-(diethylphosphinomethyl)ferrocene,1,2-bis(di-isopropylphosphinomethyl)ferrocene,1,2-bis-(diraethylphosphinomethyl)ferrocene,1,2-bis-(di-(1,3,5,7-tetramethyl-6,9,10-trioxa-2-phospha-adamantylmethyl))ferrocene,1,2-bis-(dimethylaminomethyl)ferrocene-bismethyl iodide,1,2-bis(dihydroxymethylphosphinomethyl)ferrocene,1,2-bis(diphosphinomethyl)ferrocene,1,2-bis-α,α-(P-(2,2,6,6,-tetramethylphosphinan-4-one))dimethylferrocene,and1,2-bis-(di-1,3,5,7-tetramethyl-6,9,10-trioxa-2-phospha-adamantylmethyl))benzene.Nevertheless, the skilled person in the art would appreciate that otherbidentate ligands can be envisaged without departing from the scope ofthe invention.

According to a further aspect, the present invention provides a catalystsystem capable of catalysing the carbonylation of an ethylenicallyunsaturated compound, said system comprising:

a) a metal of Group VIB or Group VIIIB or a compound thereof,

b) a bidentate phosphine, arsine, or stibine ligand, preferably abidentate phosphine ligand, and

c) an acid,

wherein said ligand is present in at least a 2:1 molar excess comparedto said metal or said metal in said metal compound, and that said acidis present in at least a 2:1 molar excess compared to said ligand.

For the avoidance of any doubt, it is hereby stated that any of thefeatures and embodiments described hereinbefore are equally applicableto this aspect.

According to a further aspect, the present invention provides a processfor the carbonylation of an ethylenically unsaturated compoundcomprising contacting an ethylenically unsaturated compound with carbonmonoxide and a hydroxyl group containing compound in the presence of acatalyst system as defined in the present invention, such as defined inthe first aspect of the present invention. Preferably, the process is aliquid phase continuous process comprising the step noted above.Nevertheless, although the process is preferably operated continuously,batch operation is possible.

According to a yet further aspect, the present invention provides aprocess for the carbonylation of an ethylenically unsaturated compoundcomprising contacting an ethylenically unsaturated compound with carbonmonoxide and a hydroxyl group containing compound in the presence of acatalyst system, said system comprising:

a) a metal of Group VIB or Group VIIIB or a compound thereof,

b) a bidentate phosphine, arsine, or stibine ligand, preferably abidentate phosphine ligand, and

c) an acid,

wherein said ligand is present in at least a 2:1 molar excess comparedto said metal or said metal in said metal compound, and that said acidis present in at least a 2:1 molar excess compared to said ligand.

Suitably, the hydroxyl group containing compound includes water or anorganic molecule having a hydroxyl functional group. Preferably, theorganic molecule having a hydroxyl functional group may be branched orlinear, and comprises an alkanol, particularly a C₁-C₃₀ alkanol,including aryl alkanols, which may be optionally substituted with one ormore substituents selected from lower alkyl, aryl, Het, halo, cyano,nitro, OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁵R²⁶,C(S)R²⁵R²⁶, SR²⁷ or C(O)SR²⁸ as defined herein. Highly preferredalkanols are C₁-C₈ alkanols such as methanol, ethanol, propanol,iso-propanol, iso-butanol, t-butyl alcohol, n-butanol, phenol andchlorocapryl alcohol. Although the monoalkanols are most preferred,poly-alkanols, preferably, selected from di-octa ols such as diols,triols, tetra-ols and sugars may also be utilised. Typically, suchpolyalkanols are selected from 1,2-ethanediol, 1,3-propanediol,glycerol, 1,2,4 butanetriol, 2-(hydroxymethyl)-1,3-propanediol, 1,2,6trihydroxyhexane, pentaerythritol, 1,1,1 tri(hydroxymethyl)ethane,nannose, sorbase, galactose and other sugars. Preferred sugars includesucrose, fructose and glucose. Especially preferred alkanols aremethanol and ethanol. The most preferred alkanol is methanol.

The amount of alcohol is not critical. Generally, amounts are used inexcess of the amount of ethylenically unsaturated compound to becarbonylated. Thus the alcohol may serve as the reaction solvent aswell, although, if desired, separate solvents may also be used.

It will be appreciated that the end product of the reaction isdetermined at least in part by the source of hydroxyl group containingcompound used. If water is used as the hydroxyl group containingcompound then the end product is the corresponding carboxylic acid,whereas use of an alkanol produces the corresponding ester.

It will also be appreciated that the process of the present inventionmay start with a catalyst system having components providing molarratios above or below those claimed but such ratios will progress tovalues within said ranges claimed during the course of the reaction.

It will of course also be appreciated that the levels of such componentspresent within the catalyst system may change during the process of theinvention as further amounts of some or all of the components are addedto maintain the usable levels of components within the catalyst system.Some of the components of the catalyst system may drop out of the systemduring the reaction process and therefore levels may need to betopped-up to maintain levels within the actual catalyst system.

As stated hereinbefore, it will be appreciated by those skilled in theart that the phosphines described herein may function as ligands thatcoordinate with the Group VIB or Group VIIIB metal or compound, togetherwith the present acid, to form a complex. This complex may representpart of the effective catalyst in the present invention and hence mayrepresent part of the catalyst system defined herein.

Thus, in a further aspect, the present invention provides a complexcapable of catalysing the carbonylation of an ethylenically unsaturatedcompound, said complex obtainable by combining:

a) a metal of Group VIB or Group VIIIB or a compound thereof,

b) a bidentate phosphine, arsine, or stibine ligand, preferably abidentate phosphine ligand, and

c) an acid,

wherein said ligand is present in at least a 2:1 molar excess comparedto said metal or said metal in said metal compound, and that said acidis present in at least a 2:1 molar excess compared to said ligand.

In a yet further aspect, the present invention provides a process forthe carbonylation of an ethylenically unsaturated compound with carbonmonoxide and a hydroxyl group containing compound in the presence of acomplex, said complex as defined above.

In the process according to the present invention, the carbon monoxidemay be used in pure form or diluted with an inert gas such as nitrogen,carbon dioxide or a noble gas such as argon. Small amounts of hydrogen,typically less than 5% by volume, may also be present.

The ratio (volume/volume) of ethylenically unsaturated compound tohydroxyl group containing compound may vary between wide limits andsuitably lies in the range of 1:0.1 to 1:10, preferably from between 2:1to 1:2 and up to a large excess of hydroxyl group containing compoundswhen the latter is also the reaction solvent such as up to a 50:1 excessof hydroxyl group containing compounds.

The molar ratio of the ethylenically unsaturated compound to carbonmonoxide is preferably in the range 1:1 to 100:1 more preferably greaterthan 1:1, even more preferably at least 3:1, especially from 3:1 to50:1, and most preferably in the range from 3:1 to 15:1.

The amount of the catalyst of the invention used in the carbonylationprocess of the ethylenically unsaturated compound is not critical. Goodresults may be obtained when, preferably, the amount of Group VIB orVIIIB metal is in the range 10⁻⁷ to 10⁻¹ moles per mole of ethylenicallyunsaturated compound, more preferably, 10⁻⁶ to 10⁻² moles, mostpreferably 10⁻⁵ to 10⁻² moles per mole of ethylenically unsaturatedcompound. Preferably, the amount of bidentate compound of formula I orformula III to unsaturated compound is in the range 10⁻⁷ to 10⁻¹, morepreferably, 10⁻⁶ to 10⁻², most preferably, 10⁻⁵ to 10⁻² moles per moleof ethylenically unsaturated compound.

Suitably, although non-essential to the invention, the carbonylation ofan ethylenically unsaturated compound as defined herein may be performedin one or more aprotic solvents. Suitable solvents include ketones, suchas for example methylbutylketone; ethers, such as for example anisole(methyl phenyl ether), 2,5,8-trioxanonane (diglyme), diethyl ether,dimethyl ether, tetrahydrofuran, diphenylether, diisopropylether and thedimethylether of di-ethylene-glycol; esters, such as for examplemethylacetate, dimethyladipate methyl benzoate, dimethyl phthalate andbutyrolactone; amides, such as for example dimethylacetamide,N-methylpyrrolidone and dimethyl formamide; sulfoxides and sulphones,such as for example dimethylsulphoxide, di-isopropylsulphone, sulfolane(tetrahydrothiophene-2,2-dioxide), 2-methylsulfolane, diethyl sulphone,tetrahydrothiophene 1,1-dioxide and 2-methyl-4-ethylsulfolane; aromaticcompounds, including halo variants of such compounds eg. benzene,toluene, ethyl benzene o-xylene, m-xylene, p-xylene, chlorobenzene,o-dichlorobenzene, m-dichlorobenzene:alkanes, including halo variants ofsuch compounds eg, hexane, heptane, 2,2,3-trimethylpentane, methylenechloride and carbon tetrachloride; nitriles eg. benzonitrile andacetonitrile.

Very suitable are aprotic solvents having a dielectric constant that isbelow a value of 50, more preferably in the range of 3 to 8, at 298.15 Kand 1×10⁵ Nm⁻². In the present context, the dielectric constant for agiven solvent is used in its normal meaning of representing the ratio ofthe capacity of a condenser with that substance as dielectric to thecapacity of the same condenser with a vacuum for dielectric. Values forthe dielectric constants of common organic liquids can be found ingeneral reference books, such as the Handbook of Chemistry and Physics,76^(th) edition, edited by David R. Lide et al, and published by CRCpress in 1995, and are usually quoted for a temperature of about 20° C.or 25° C., i.e. about 293.15 k or 298.15 K, and atmospheric pressure,i.e. about 1×10⁵ Nm⁻², or can readily be converted to that temperatureand pressure using the conversion factors quoted. If no literature datafor a particular compound is available, the dielectric constant may bereadily measured using established physico-chemical methods.

For example, the dielectric constant of anisole is 4.3 (at 294.2 K), ofdiethyl ether is 4.3 (at 293.2 K), of sulfolane is 43.4 (at 303.2 K), ofmethylpentanoate is 5.0 (at 293.2 K), of diphenylether is 3.7 (at 283.2K), of dimethyladipate is 6.8 (at 293.2 K), of tetrahydrofuran is 7.5(at 295.2 K), of methylnonanoate is 3.9 (at 293.2 K). A preferredsolvent is anisole.

If the hydroxyl group containing compound is an alkanol, an aproticsolvent will be generated by the reaction as the ester carbonylationproduct of the ethylenically unsaturated compound, carbon monoxide andthe alkanol is an aprotic solvent.

The process may be carried out in an excess of aprotic solvent, i.e. ata ratio (v/v) of aprotic solvent to hydroxyl group containing compoundof at least 1:1. Preferably, this ratio ranges from 1:1 to 10:1 and morepreferably from 1:1 to 5:1. Most preferably the ratio (v/v) ranges from1.5:1 to 3:1.

Despite the a foregoing it is preferred that the reaction is carried outin the absence of any external added aprotic solvent i.e. an aproticsolvent not generated by the reaction itself.

The catalyst compounds of the present invention may act as a“heterogeneous” catalyst or a “homogeneous” catalyst.

By the term “homogeneous” catalyst we mean a catalyst, i.e. a compoundof the invention, which is not supported but is simply admixed or formedin-situ with the reactants of the carbonylation reaction (e.g. theethylenically unsaturated compound, the hydroxyl containing compound andcarbon monoxide), preferably in a suitable solvent as described herein.

By the term “heterogeneous” catalyst we mean a catalyst, i.e. thecompound of the invention, which is carried on a support.

Thus according to a further aspect, the present invention provides aprocess for the carbonylation of ethylenically unsaturated compounds asdefined herein wherein the process is carried out with the catalystcomprising a support, preferably an insoluble support.

Preferably, the support comprises a polymer such as a polyolefin,polystyrene or polystyrene copolymer such as a divinylbenzene copolymeror other suitable polymers or copolymers known to those skilled in theart; a silicon derivative such as a functionalised silica, a silicone ora silicone rubber; or other porous particulate material such as forexample inorganic oxides and inorganic chlorides.

Preferably the support material is porous silica which has a surfacearea in the range of from 10 to 700 m²/g, a total pore volume in therange of from 0.1 to 4.0 cc/g and an average particle size in the rangeof from 10 to 500 μm. More preferably, the surface area is in the rangeof from 50 to 500 m²/g, the pore volume is in the range of from 0.5 to2.5 cc/g and the average particle size is in the range of from 20 to 200μm. Most desirably the surface area is in the range of from 100 to 400m²/g, the pore volume is in the range of from 0.8 to 3.0 cc/g and theaverage particle size is in the range of from 30 to 100 μm. The averagepore size of typical porous support materials is in the range of from 10to 1000 {acute over (Å)}. Preferably, a support material is used thathas an average pore diameter of from 50 to 500 {acute over (Å)}, andmost desirably from 75 to 350 {acute over (Å)}. It may be particularlydesirable to dehydrate the silica at a temperature of from 100° C. to800° C. anywhere from 3 to 24 hours.

Suitably, the support may be flexible or a rigid support, the insolublesupport is coated and/or impregnated with the compounds of the processof the invention by techniques well known to those skilled in the art.

Alternatively, the compounds of the process of the invention are fixedto the surface of an insoluble support, optionally via a covalent bond,and the arrangement optionally includes a bifunctional spacer moleculeto space the compound from the insoluble support.

The compounds of the invention may be fixed to the surface of theinsoluble support by promoting reaction of a functional group present inthe compound of formula I or III, for example a substituent K, D, Z andE (or K¹, D¹ and E¹) of the aryl moiety, with a complimentary reactivegroup present on or previously inserted into the support. Thecombination of the reactive group of the support with a complimentarysubstituent of the compound of the invention provides a heterogeneouscatalyst where the compound of the invention and the support are linkedvia a linkage such as an ether, ester, amide, amine, urea, keto group.

The choice of reaction conditions to link a compound of the process ofthe present invention to the support depend upon the ethylenicallyunsaturated compound and the groups of the support. For example,reagents such as carbodiimides, 1,1′-carbonyldiimidazole, and processessuch as the use of mixed anhydrides, reductive amination may beemployed.

According to a further aspect, the present invention provides the use ofthe process of any aspect of the invention wherein the catalyst isattached to a support.

Conveniently, the process of the invention may be carried out bydissolving the Group VIB or VIIIB metal or compound thereof as definedherein in a suitable solvent such as one of the hydroxyl groupcontaining compounds or aprotic solvents previously described (aparticularly preferred solvent would be the ester or acid product of thespecific carbonylation reaction e.g. Methyl propionate for ethylenecarbonylation) and subsequently admixing with a compound of formula I orIII as defined herein and an acid.

The carbon monoxide may be used in the presence of other gases which areinert in the reaction. Examples of such gases include hydrogen,nitrogen, carbon dioxide and the noble gases such as argon.

Suitable Group VIB or VIIIB metals or a compound thereof which may becombined with a compound of formula I or III include cobalt, nickel,palladium, rhodium, platinum, chromium, molybdenum and tungsten,preferably include cobalt, nickel, palladium, rhodium and platinum.Preferably, component a) is a Group VIIIB metal or a compound thereof.Preferably, the metal is a Group VIIIB metal, such as palladium.Preferably, the Group VIIIB metal is palladium or a compound thereof.Thus, component a) is preferably palladium or a compound thereof.Suitable compounds of such Group VIB or VIIIB metals include salts ofsuch metals with, or compounds comprising weakly coordinated anionsderived from, nitric acid; sulphuric acid; lower alkanoic (up to C₁₂)acids such as acetic acid and propionic acid; sulphonic acids such asmethane sulphonic acid, chlorosulphonic acid, fluorosulphonic acid,trifluoromethane sulphonic acid, benzene sulphonic acid, naphthalenesulphonic acid, toluene sulphonic acid, e.g. p-toluene sulphonic acid,t-butyl sulphonic acid, and 2-hydroxypropane sulphonic acid; sulphonatedion exchange resins; perhalic acid such as perchloric acid; halogenatedcarboxylic acids such as trichloroacetic acid and trifluoroacetic acid;orthophosphoric acid; phosphonic acids such as benzenephosphonic acid;and acids derived from interactions between Lewis acids and Broenstedacids. Other sources which may provide suitable anions include theoptionally halogenated tetraphenyl borate derivatives, e.g.perfluorotetraphenyl borate. Additionally, zero valent palladiumcomplexes particularly those with labile ligands, e.g.triphenylphosphine or alkenes such as dibenzylideneacetone or styrene ortri(dibenzylideneacetone)dipalladium may be used. Nevertheless, an acidis present in the catalyst system as set out hereinbefore, even if othersources of anion such as those noted above are also present.

Thus, the acid is selected from an acid having a pKa measured in aqueoussolution at 18° C. of less than 4, more preferably less than 3, mostpreferably less than 2. Suitable acids include the acids listed supra.Preferably, the acid is not a carboxylic acid, more preferably the acidis either a sulphonic acid, or some other non-carboxylic acid such asthose selected from the list consisting of perchloric acid, phosphoricacid, methyl phosphonic acid, sulphuric acid, and sulphonic acids, evenmore preferably a sulphonic acid or other non-carboxylic acid (selectedfrom the list above) having a pKa measured in aqueous solution at 18° C.of less than 2, yet even more preferably a sulphonic acid having a pKameasured in aqueous solution at 18° C. of less than 2, still morepreferably the acid is selected from the list consisting of thefollowing sulphonic acids: methanesulphonic acid,trifluoromethanesulphonic acid, tert-butanesulphonic acid,p-toluenesulphonic acid, 2-hydroxypropane-2-sulphonic acid, and2,4,6-trimethylbenzenesulphonic acid, most preferably the acid ismethanesulphonic acid.

As mentioned, the catalyst system of the present invention may be usedhomogeneously or heterogeneously. Preferably, the catalyst system isused homogeneously.

The catalyst system of the present invention is preferably constitutedin the liquid phase which may be formed by one or more of the reactantsor by the use of a suitable solvent.

The molar ratio of the amount of ethylenically unsaturated compound usedin the reaction to the amount of hydroxyl providing compound is notcritical and may vary between wide limits, e.g. from 0.001:1 to 100:1mol/mol.

The product of the carbonylation reaction using the ligand of theinvention may be separated from the other components by any suitablemeans. However, it is an advantage of the present process thatsignificantly fewer by-products are formed thereby reducing the need forfurther purification after the initial separation of the product as maybe evidenced by the generally significantly higher selectivity. Afurther advantage is that the other components which contain thecatalyst system which may be recycled and/or reused in further reactionswith minimal supplementation of fresh catalyst.

Preferably, the carbonylation is carried out at a temperature of between−10 to 150° C., more preferably 0° C. to 140° C., even more preferably15° C. to 140° C., most preferably 20° C. to 120° C. An especiallypreferred temperature is one chosen between 80° C. to 120° C.Advantageously, the carbonylation can be carried out at moderatetemperatures, it is particularly advantageous to be able to carry outthe reaction at room temperature (20° C.).

Preferably, when operating a low temperature carbonylation, thecarbonylation is carried out between −30° C. to 49° C., more preferably,−10° C. to 45° C., still more preferably 0° C. to 45° C., even morepreferably 10° C. to 45° C., most preferably 15° C. to 45° C. Especiallypreferred is a range of 15 to 35° C.

Preferably, the carbonylation is carried out at a CO partial pressure ofbetween 0.80×10⁵ N·m⁻²−90×10⁵ N·m⁻², more preferably 1×10⁵ N·m⁻²−65×10⁵N·m⁻², most preferably 1−30×10⁵ N·m⁻². Especially preferred is a COpartial pressure of 5 to 20×10⁵ N·m⁻².

Preferably, a low pressure carbonylation is also envisaged. Preferably,when operating a low pressure carbonylation the carbonylation is carriedout at a CO partial pressure of between 0.1 to 5×10⁵ N·m⁻², morepreferably 0.2 to 2×10⁵ N·m⁻², most preferably 0.5 to 1.5×10⁵ N·m⁻².

The ethylenically unsaturated compounds may be substituted ornon-substituted with groups as defined above for the “aryl” group above.Particularly suitable substituents include alkyl and aryl groups as wellas groups containing heteroatoms such as halides, sulphur, phosphorus,oxygen and nitrogen. Examples of substituents include chloride, bromide,iodide and hydroxy, alkoxy, carboxy, amino, amido, nitro, cyano, thiolor thioalkoxy groups. Suitable ethylenically unsaturated compoundsinclude ethene, propene, hexene, vinyl compounds such as vinyl acetates,heptene, octene, nonene, decene, undecene, dodecene, etc up to C₃₀, i.e.having from 2 to 30 carbon atoms, which may be linear or branched,cyclic or uncyclic or part cyclic and in which the double bond may takeany suitable position in the carbon chain and which includes allstereisomers thereof.

Moreover, the unsaturated compound may have one or more unsaturatedbonds and therefore, for example, the range of ethylenically unsaturatedcompounds extends to dienes. The unsaturated bond(s) may be internal orterminal, the catalyst system of the invention being particularlyadvantageous in the conversion of internal olefins.

Particularly preferred are olefins having from 2 to 22 carbon atoms permolecule, such as ethene, propene, 1-butene, 2-butene, isobutene,pentenes, hexenes, octenes, e.g. oct-2-ene, oct-3-ene, oct-4-ene,decenes and dodecenes, triisobutylene, tripropylene, internal C₁₄olefins, and internal C₁₅-C₁₈ olefins, 1,5-cyclooctadiene,cyclododecene, methyl pentenoate and pentene nitriles, e.g. pent-2-enenitrile.

The ethylenically unsaturated compound is preferably an alkene having 1to 3 carbon-carbon double bonds per molecule. Non-limiting examples ofsuitable dienes include the following: 1,3-butadiene,2-methyl-1,3-butadiene, 1,5-cyclooctadiene, 1,3-cyclohexadiene,2,4-heptadiene, 1,3-pentadiene, 1,3-hexadiene, particularly1,3-butadiene.

Another preferred category of unsaturated compounds consists ofunsaturated esters of carboxylic acids and esters of unsaturatedcarboxylic acids. For example, the starting material may be a vinylester of a carboxylic acid such as acetic acid or propanoic acid, or itmay be an alkyl ester of an unsaturated acid, such as the methyl orethyl ester of acrylic acid or methacrylic acid.

A further preferred category of unsaturated compounds consists ofcycloalkadienes, which will ordinarily refuse carbonylation. Forexample, the starting material may be dicyclopentadiene ornorbornadiene, to give diesters, diamides or diacids, etc., which mayfind subsequent use as monomers in polymerisation reactions.

The use of stabilising compounds with the catalyst system may also bebeneficial in improving recovery of metal which has been lost from thecatalyst system. When the catalyst system is utilized in a liquidreaction medium such stabilizing compounds may assist recovery of theGroup VI or VIIIB metal.

Preferably, therefore, the catalyst system includes in a liquid reactionmedium a polymeric dispersant dissolved in a liquid carrier, saidpolymeric dispersant being capable of stabilising a colloidal suspensionof particles of the Group VI or VIIIB metal or metal compound of thecatalyst system within the liquid carrier.

The liquid reaction medium may be a solvent for the reaction or maycomprise one or more of the reactants or reaction products themselves.The reactants and reaction products in liquid form may be miscible withor dissolved in a solvent or liquid diluent.

The polymeric dispersant is soluble in the liquid reaction medium, butshould not significantly increase the viscosity of the reaction mediumin a way which would be detrimental to reaction kinetics or heattransfer. The solubility of the dispersant in the liquid medium underthe reaction conditions of temperature and pressure should not be sogreat as to deter significantly the adsorption of the dispersantmolecules onto the metal particles.

The polymeric dispersant is capable of stabilising a colloidalsuspension of particles of said Group VI or VIIIB metal or metalcompound within the liquid reaction medium such that the metal particlesformed as a result of catalyst degradation are held in suspension in theliquid reaction medium and are discharged from the reactor along withthe liquid for reclamation and optionally for re-use in making furtherquantities of catalyst. The metal particles are normally of colloidaldimensions, e.g. in the range 5-100 nm average particle size althoughlarger particles may form in some cases. Portions of the polymericdispersant are adsorbed onto the surface of the metal particles whilstthe remainder of the dispersant molecules remain at least partiallysolvated by the liquid reaction medium and in this way the dispersedGroup VI or VIIIB metal particles are stabilised against settling on thewalls of the reactor or in reactor dead spaces and against formingagglomerates of metal particles which may grow by collision of particlesand eventually coagulate. Some agglomeration of particles may occur evenin the presence of a suitable dispersant but when the dispersant typeand concentration is optimised then such agglomeration should be at arelatively low level and the agglomerates may form only loosely so thatthey may be broken up and the particles redispersed by agitation.

The polymeric dispersant may include homopolymers or copolymersincluding polymers such as graft copolymers and star polymers.

Preferably, the polymeric dispersant has sufficiently acidic or basicfunctionality to substantially stabilise the colloidal suspension ofsaid Group VI or VIIIB metal or metal compound.

By substantially stabilise is meant that the precipitation of the GroupVI or VIIIB metal from the solution phase is substantially avoided.

Particularly preferred dispersants for this purpose include acidic orbasic polymers including carboxylic acids, sulphonic acids, amines andamides such as polyacrylates or heterocycle, particularly nitrogenheterocycle, substituted polyvinyl polymers such as polyvinylpyrrolidone or copolymers of the aforesaid.

Examples of such polymeric dispersants may be selected frompolyvinylpyrrolidone, polyacrylamide, polyacrylonitrile,polyethylenimine, polyglycine, polyacrylic acid, polymethacrylic acid,poly(3-hydroxybutyricacid), poly-L-leucine, poly-L-methionine,poly-L-proline, poly-L-serine, poly-L-tyrosine,poly(vinylbenzenesulphonic acid) and poly(vinylsulphonic acid).

Preferably, the polymeric dispersant incorporates acidic or basicmoieties either pendant or within the polymer backbone. Preferably, theacidic moieties have a dissociation constant (pK_(a)) of less than 6.0,more preferably, less than 5.0, most preferably less than 4.5.Preferably, the basic moieties have a base dissociation constant(pK_(b)) being of less than 6.0, more preferably less than 5.0 and mostpreferably less than 4.5, pK_(a) and pK_(b) being measured in diluteaqueous solution at 25° C.

Suitable polymeric dispersants, in addition to being soluble in thereaction medium at reaction conditions, contain at least one acidic orbasic moiety, either within the polymer backbone or as a pendant group.We have found that polymers incorporating acid and amide moieties suchas polyvinylpyrollidone (PVP) and polyacrylates such as polyacrylic acid(PAA) are particularly suitable. The molecular weight of the polymerwhich is suitable for use in the invention depends upon the nature ofthe reaction medium and the solubility of the polymer therein. We havefound that normally the average molecular weight is less than 100,000.Preferably, the average molecular weight is in the range 1,000-200,000,more preferably, 5,000-100,000, most preferably, 10,000-40,000 e.g. Mwis preferably in the range 10,000-80,000, more preferably 20,000-60,000when PVP is used and of the order of 1,000-10,000 in the case of PAA.

The effective concentration of the dispersant within the reaction mediumshould be determined for each reaction/catalyst system which is to beused.

The dispersed Group VI or VIIIB metal may be recovered from the liquidstream removed from the reactor e.g. by filtration and then eitherdisposed of or processed for re-use as a catalyst or other applications.In a continuous process the liquid stream may be circulated through anexternal heat-exchanger and in such cases it may be convenient to locatefilters for the palladium particles in these circulation apparatus.

Preferably, the polymer:metal mass ratio in g/g is between 1:1 and1000:1, more preferably, between 1:1 and 400:1, most preferably, between1:1 and 200:1. Preferably, the polymer:metal mass ratio in g/g is up to1000, more preferably, up to 400, most preferably, up to 200.

According to a further aspect there is provided a reaction mediumcomprising one or more reactants, and a catalyst system comprising, orobtainable by combining, at least a Group VIB or VIIIB metal or metalcompound, a bidentate phosphine, arsine, or stibine ligand, and an acid,as defined herein, wherein said ligand is present in at least a 2:1molar excess compared to said metal or said metal in said metalcompound, and that said acid is present in at least a 2:1 molar excesscompared to said ligand.

Preferably, said reaction medium is a liquid-phase reaction medium, morepreferably a liquid-phase continuous-system reaction system.

Preferably, within said reaction medium, the amount of free acid presentin the medium, that is acid which is not directly combined with thephosphine ligand, is greater than 500 ppm, more preferably greater than1000 ppm, most preferably greater than 2000 ppm.

According to a further aspect the invention provides a process forpreparing the catalyst systems of the invention comprising combiningcomponents a), b) and c) as defined herein, preferably in theaforementioned ratios.

According to a yet further aspect the present invention provides the useof a system comprising, or obtainable by combining:

a) a metal of Group VIB or Group VIIIB or a compound thereof,

b) a bidentate phosphine, arsine, or stibine ligand, preferably abidentate phosphine ligand, and

c) an acid,

wherein said ligand is present in at least a 2:1 molar excess comparedto said metal or said metal in said metal compound, and that said acidis present in at least a 2:1 molar excess compared to said ligand, as acatalyst in the carbonylation of an ethylenically unsaturated compound,preferably the liquid-phase carbonylation of an ethylenicallyunsaturated compound, more preferably the liquid-phase continuous-systemcarbonylation of an ethylenically unsaturated compound.

For the avoidance of any doubt, each and every feature describedhereinbefore is equally applicable to any or all of the various aspectsof the present invention as set out herein, unless such features areincompatible with the particular aspect or are mutually exclusive.

All documents mentioned herein are incorporated by reference thereto.

The following examples further illustrate the present invention. Theseexamples are to be viewed as being illustrative of specific materialsfalling within the broader disclosure presented above and are not to beviewed as limiting the broader disclosure in any way.

Example 1 Preparation of 1,2 bis(diadamantylphosphinomethyl)benzene

(Method 1)

The preparation of this ligand was carried out as follows.

1.1 Preparation of (1-Ad)₂P(O)Cl

Phosphorous trichloride (83 cm³, 0.98 mol) was added rapidly via cannulato a combination of aluminium chloride (25.0 g, 0.19 mol) and adamantane(27.2 g, 0.20 mol) affording a tan suspension. The reaction was heatedto reflux. After 10 mins, a yellow-orange suspension was formed. Thereaction was refluxed for a total of 6 h. The excess PCl₃ was removed bydistillation at atmospheric pressure (BP 75° C.). On cooling to ambienttemperature, an orange solid was formed. Chloroform (250 cm³) was addedyielding an orange suspension, which was cooled to 0° C. Water (150 cm³)was added slowly: initially the suspension viscosity increased, but onfull addition of water the viscosity lessened. From this point thereaction was no longer kept under an atmosphere of Ar. The suspensionwas Buchner filtered to remove the yellow-orange solid impurity. Thefiltrate consisted of a two phase system. The lower phase was separatedusing a separating funnel, dried over MgSO₄ and Buchner filtered. Thevolatiles were removed via rotary evaporation, drying finally in-vacuo,affording an off-white powder. Yield 35.0 g, 99%. ³¹P NMR: δ=85 ppm, 99%pure. FW=352.85.

1.2 Preparation of (1-Ad)₂PH

LiAlH₄ (2.54 g, 67.0 mmol) was added over 90 minutes to a chilled (−10°C.) solution of (1-Ad)₂P(O)Cl (10.00 g, 28.3 mmol) in THF. (120 cm³).The reaction was allowed to warm to ambient temperature then stirred for20 h. The grey suspension was cooled to −10° C. HCl (aq., 5 cm³ c. HClin 50 cm³ degassed water) was added slowly via syringe (initially veryslowly due to exotherm of reaction), yielding a two phase system, withsome solid material in the lower phase. Further HCl (˜5 cm³ c. HCl) wasadded to improve the separation of the layers. The upper phase wasremoved via flat ended cannula, dried over MgSO₄ and filtered viacannula. The volatiles were removed in-vacuo affording the product as awhite powder, isolated in the glovebox. Yield 6.00 g, 70%. ³¹P NMR: δ=17ppm, 100% pure. FW=302.44.

1.3 Preparation of (1-Ad)₂PCl

A solution of Ad₂PH (10.5 g, 34.7 mmol) and DBU (6.12 cm³, 40.9 mmol) intoluene (250 cm³) was chilled to −10° C. Phosgene solution (30.0 cm³,56.7 mmol, was added slowly via cannula, transferring via a measuringcylinder. This afforded a highly viscous pale yellow suspension.Additional toluene (100 cm³) was added via cannula to lessen theviscosity and ease the stirring. The reaction was filtered via cannulaaffording a yellow filtrate. The residue was washed with additionaltoluene (2×100 cm³) and the washings combined with the originalfiltrate. The volatiles were removed in-vacuo affording a pale yellowsolid, which was washed with pentane (2×30 cm³, washings practicallycolourless). The product was dried in-vacuo and isolated in the gloveboxas a lemon yellow powder. Yield 7.84 g, 67%. ³¹P NMR: δ=139 ppm, 99+%pure. FW=336.88.

1.4 Preparation of 1,2-bis(di-1-adamantylphosphinomethyl)benzene

1.4.1 Preparation of DI-SODIO-ORTHO-XYLENE(DISOD)

Bu^(n)Li (2.5 M in hexanes, 11.28 cm³, 28.2 mmol) was added dropwise viasyringe over 15 minutes to a stirred suspension of NaOBu^(t) (crushed,2.71 g, 28.2 mmol), o-xylene (1.15 cm³, 9.4 mmol) andN,N,N′,N′-tetramethyl ethylene diamine (TMEDA) (4.26 cm³, 28.2 mmol) inheptane (100 cm³). The reaction was heated at 60° C. for 2 h, thenallowed to cool/settle, affording a bright orange solid (DISOD) and paleyellow solution. The solution was removed via cannula filtration and thesolid washed with additional heptane (50 cm³) and dried in-vacuo. 90%yield assumed, 8.47 mmol.

1.4.2 Reaction of DI-SODIO-ORTHO-XYLENE with 2 equiv (1-Ad)₂PCl

A suspension of DISOD (8.47 mmol) in Et₂O (100 cm³) was prepared at −78°C. A suspension of Ad₂PCl (5.70 g, 16.9 mmol) in Et₂O (120 cm³) wasstirred rapidly at −78° C. and added via wide-bore cannula to the DISODsuspension. The reaction was allowed to warm to ambient temperature andstirred for 18 h, affording a pale yellow turbid solution. Water(degassed, 100 cm³) added via cannula affording a two phase system, witha great deal of white solid present (product) due to the low solubilityof this material. The upper phase (Et₂O) was removed via cannula. Thesolid in the aqueous phase was extracted using dichloromethane (200cm³), forming two clear phases. The lower phase (CH₂Cl₂) was removed viacannula and combined with the original Et₂O phase. The volatiles wereremoved in-vacuo yielding a slightly sticky solid. The solid was washedwith pentane (200 cm³) with attrition being performed, the washingsbeing removed via cannula filtration. The white solid was dried in-vacuoand isolated in the glovebox as a friable white powder. Yield 3.5 g,59%. FW=707.01.

³¹P {¹H} NMR data: δ 24 ppm.

¹H NMR data: (400 MHz, CDCl₃, 298 K) δ 7.59-7.50 (m, 2H, Ar—H),7.09-6,99 (m, 2H, Ar—H), 3.01 (d, 4H, ²J_(PH)=3.2 Hz, CH₂), 2.07-1.57(m, 60H, C₁₀H₁₅) ppm.

¹³C {¹H} NMR data: (100 MHz, CDCl₃, 298 K) Γ 139.4 (dd, J_(PC)=10.7 Hz,J_(PC)=2.3 Hz, Ar—C), 131.0 (d, J_(PC)=16.8 Hz, Ar—C), 125.0 (s, Ar—C),41.1 (d, ²J_(PC)=10.7 Hz, Ad-C²), 37.2 (s, Ad-C⁴), 36.9 (d, ¹J_(PC)=22.9Hz, Ad-C¹), 28.8 (d, ³J_(PC)=7.6 Hz, Ad-C³), 22.0 (dd, ¹J_(PC)=22.9 Hz,⁴J_(PC)=3.1 Hz, CH₂).

Example 2 Preparation of 1,2 bis(diadamantylphosphinomethyl)benzene(method 2)

2.1 Di-1-adamantyl phosphinic chloride was prepared in accordance withthe method of Example 1.1.

2.2 Di-1-adamantyl phosphine was prepared in accordance with the methodof Example 1.2.

2.3 (Di-1-adamantyl phosphine)trihydro boron. Borane (THP) adduct (10cm³, 10 mmol) was added to stirred solution of di-1-adamantyl phosphine(1.36 g, 4.5 mmol) in THP (30 cm³). Stirring for a further 5 hrsafforded a slightly turbid solution. The volatiles were then removedin-vacuo to yield the product as a pure white solid. Yield: 1.39 g, 98%,99% pure. FW: 315.25. ³¹P NMR: δ 41 ppm (d, J_(PB) 64 Hz).

2.4 Synthesis of 1,2 bis(di-1-adamantylphosphor(borane)methyl)benzenevia deprotonation with ^(sec)BuLi and reaction with αα dichloroo-xylene. To a stirred, cooled (−78°) THF solution (60 cm³) ofdi-1-adamantyl phosphine trihydroboron (5 g, 15.8 mmol), was slowlyadded (via syringe) ^(sec)BuLi (12.3 cm³, 16.6 mmol), upon full additionthe solution had a noticeable yellow colouration. The solution wasstirred for 30 minutes at −78° and then allowed to warm to roomtemperature and stir for a further 120 minutes. The solution was thencooled to −78° and a THF solution (20 cm³) of αα dichloro o-xylene wasadded via cannula. The solution was then allowed to warm to roomtemperature and stirred for 15 hrs. The volatiles where then removedin-vacuo. No further work up was required as LiCl and excess organicsare removed during the deprotection procedure. Yield: 100% 85% pure.

³¹P {¹H} NMR (CDCl₃, 298K) δ (d, br) 41 ppm.

¹¹B {¹H} NMR δ −43 ppm (d, J_(BP) 44 Hz)

¹H NMR (CDCl₃, 298K) δ 7.8-7.50 ppm (m, br Ar—H), δ 7.49-7.00 ppm (m, brAr—H), δ 3.3 ppm (d, CH₂), δ 2.2-1.2 ppm (m, C₁₀H₁₅)

2.5 Synthesis of 1,2-bis(di-adamantylphosphinomethyl)benzene viadeprotection of 1,2 bis(di-adamantylphosphor(borane)methyl)benzene withHBF₄.O(ME)₂.

Tetrafluoroboric acid dimethyl ether complex (5 equivalents, 12.5 mmols,1.5 cm³) was added slowly via syringe to a cooled (0° C.) stirredsolution of 1,2 bis(di-adamantylphosphor(borane)methyl benzene (70 cm³dichloromethane). The solution was stirred at 0° C. for 1 hour and thenallowed to warm to ambient temperature and stir for a further 12 hours.The reaction mixture was then added to a cooled (0° C.) saturatedsolution (degassed) NaHCO₃ solution (5*excess NaHCO₃) and stirredvigorously for 50 minutes. The organic phase was then extracted with2*30 cm³ portions of diethyl ether, and added to the DCM extract. Theorganic layers were then washed with 2×30 cm³ portions of degassed waterand dried over MgSO₄. The volatiles were then removed in-vacuo.

³¹P {¹H} NMR: δ 26.4 ppm (s).

H¹ NMR (CDCl₃, 298K) δ 7.54 ppm (q, Ar—H, J_(HH) 3.4 Hz), 7.0 ppm (q,Ar—H, J_(HH) 3.4 Hz), 3.0 ppm (d, br CH₂) 1.6-2.1 ppm (m, br C₁₀H₁₅).

Example 3

Preparation of 1,2 bis(di-3,5-dimethyladamantylphosphinomethyl)benzene(method 2)

3.1 Di-1-(3,5-dimethyladamantyl)phosphinic chloride was prepared inaccordance with the method of Example 2.1 except using 1,3dimethyladamantane 21.7 g (0.132 mol) instead of adamantane, and AlCl₃(18.5 gg, 0.14 mol). Yield 23.5 g FW: 409.08. ³¹P NMR: δ: 87 ppm (s).

3.2 Di-1-(3,5-dimethyladamantyl)phosphine was prepared as per Example2.2 above except using 25.0 g Di-1-(3,5-dimethyladamantyl)phosphinicchloride instead of di-1-adamantyl phosphonic chloride Yield 15.7 g FW:358.58. ³¹P NMR: δ: 15.7 ppm (s).

3.3 Di-1-(3,5-dimethyladamantyl)phosphine}trihydro boron was prepared asper Example 2.3 above except using 10.0 gDi-1-(3,5-dimethyladamantyl)phosphine instead of di-1-adamantylphosphine. Yield 9.5 g ³¹P NMR: δ: 40.5 ppm (br).

3.4 Synthesis of 1,2 bis(di-3,5-dimethyladamantyl(borane)methyl)benzenevia deprotonation with ^(sec)BuLi and reaction with αα dichloro o-xylenewas prepared as per Example 2.4 above except using equimolar amounts ofdi-3,5-dimethyl adamantyl phosphine trihydroboron instead ofdi-1-adamantyl phosphine trihydroboron.

3.5 Synthesis of 1,2 bis(di-3,5-dimethyladamantylphosphinomethyl)benzenevia deprotection of 1,2 bis(di-3,5-dimethyladamantylphosphor(borane)methyl)benzene with HBF₄.O(ME)₂ was prepared as per 1,2bis(di-1-adamantylphosphinomethyl)benzene (Example 2.5) above except byusing equimolar amounts of 1,2bis(di-3,5-dimethyadamantylphosphor(borane)methyl)benzene instead of 1,2bis(di-adamantylphosphor(borane)methyl)benzene.

Example 4

Preparation of 1,2 bis(di-5-tert-butyladamantylphosphinomethyl)benzene(method 2)

4.1 Di-1-(5-tert-butyladamantyl)phosphinic chloride was prepared as perDi-1-adamantyl phosphinic chloride above except usingtert-butyladamantane 25.37 g (0.132 mol) instead of adamantane, andAlCl₃ (18.5 gg, 0.14 mol). Yield 22.6 g FW: 464.98. ³¹P NMR: δ: 87 ppm(s).

4.2.1 Di-1-(5-tert-butyladamantyl)phosphine was prepared as perDi-1-adamantyl phosphine above except using 13.5 gDi-1-(5-tert-butyladamantyl)phosphinic chloride instead ofdi-1-adamantyl phosphinic chloride. Yield 9.4 g FW: 414.48. ³¹P NMR: δ:18.62 ppm (s).

4.2.2 Di-1-(5-tert-butyladamantyl)phosphine)trihydro boron was preparedas per Di-1-adamantyl phosphine above except using 10.0 gDi-1-(5-tert-butyladamantyl)phosphine instead of di-1-adamantylphosphine. Yield 9.5 g ³¹P NMR: δ: 41.6 ppm (br).

4.2.3 Synthesis of 1,2bis(di-5-tert-butyladamantylphosphor(borane)methyl)benzene viadeprotonation with ^(sec)BuLi and reaction with αα dichloro o-xylene wasprepared as per 1,2 bis(di-1-adamantylphosphor(borane)methyl)benzeneabove except using equimolar amounts ofdi-1-(5-tert-butyladamantyl)phosphine trihydroboron instead ofdi-1-adamantyl phosphine trihydroboron.

4.3 Synthesis of 1,2 bis(di-5-tert-butyladamantylphosphinomethyl)benzenevia deprotection of 1,2 bis(di-4-tert-butyladamantylphosphor(borane)methyl)benzene with HBF₄.O(ME)₂ was prepared as per 1,2bis(di-1-adamantylphosphinomethyl)benzene above except 1,2bis(di-5-tert-butyladamantylphosphor(borane)methyl)benzene was usedinstead of 1,2 bis(di-adamantylphosphor(borane)methyl)benzene inequimolar amounts.

Example 5

Preparation of 1,2 bis(1-adamantyl tert-butyl-phosphinomethyl)benzene(method 2)

5.1. 1-adamantylphosphonic acid dichloride. This compound wassynthesised according to the method of Olah et al (J. Org. Chem. 1990,55, 1224-1227).

5.2 1-adamantyl phosphine. LiAlH₄ (3.5 g, 74 mmol) was added over 2 hrsto a cooled solution (0° C.) of 1-adamantylphosphonic acid dichloride(15 g, 59 mmol) in THF (250 cm³). The reaction was then allowed to warmto ambient temperature and was stirred for 20 hrs. The grey suspensionwas then cooled (0° C.) and HCl (75 cm³, 1M) was slowly added viasyringe, to afford a two phase system with some solid present in thelower phase. Concentrated HCl (8 cm³, 11M) was then added to improve theseparation of the two layers. The (upper) THF phase was removed viacannula and dried over magnesium sulphate. After filtration via cannula,the volatiles were removed in-vacuo to afford the product.

5.3 (1-adamantyl-tert-butyl phosphine)trihydro boron. nBuLi (20 cm³, 32mmol 1.6M soln) was added over 1 hour to a cooled solution of1-adamantyl phosphine (5.0 g 3.0 mmol) in THF (100 cm³). The solutionwas allowed to warm to room temperature and stirred for a further 2hours. The solution was recooled to 0° C. and tert-butylchloride (2.78g, 30 mmol) was added and stirring continued for a further 16 hours atroom temperature. The material was isolated as the borane adduct byaddition of Borane (THF) adduct (30 cm³, 30 mmol) followed by removal ofthe solvent. The material was isolated as a white solid which was amixture of isomers.

5.4 Synthesis of 1,2 bis(1-adamantyl-tert-butylphosphor(borane)methyl)benzene via deprotonation with ^(sec)BuLi andreaction with αα dichloro o-xylene. The synthesis was carried out as per1,2 bis(di-1-adamantylphosphor(borane)methyl)benzene above exceptequimolar amounts of 1-adamantyl-tert-butyl(phosphine)trihydroboron wereused instead of the di-1-adamantyl phosphine trihydroboron.

5.5 Synthesis of 1,2 bis(1-adamantyl-tert-butylphosphinomethyl)benzenevia deprotection of 1,2 bis(1-adamantyl-tert-butylphosphor(borane)methyl)benzene with HBF₄.O(ME)₂. As per 1,2bis(di-adamantylphosphorinomethyl)benzene except using equimolar amountsof 1,2 bis(1-adamantyl-tert-butyl phosphor(borane)methyl)benzene insteadof 1,2 bis) (di-adamantylphosphor(borane)methyl)benzene.

Example 6

Preparation of 1,2 bis(di-1-diamantanephosphinomethyl) benzene.Diamantane=congressane

6.1 Diamantane. This was synthesised according to the method of Tamaraet al. Organic Syntheses, CV 6, 378

6.2 Di-1-(diamantane)phosphinic chloride. Prepared as per Di-1-adamantylphosphinic chloride except using diamantane 20.0 g (0.106 mol) and AlCl₃(16.0 g, 0.12 mol). Yield 25.5 g FW: 456.5. ³¹P NMR: δ: 87 ppm (s).

6.3 Di-1-(diamantane)phosphine. Prepared as per Di-1-adamantyl phosphineexcept using 25.0 g Di-1-(diamantane)phosphinic chloride. Yield 14.0 gFW: 406. ³¹P NMR: δ: 16.5 ppm (s).

6.4 Di-1-(diamantane)phosphine}trihydro boron. Prepared as perDi-1-adamantyl phosphine trihydro boron except using 15.0 gDi-1-(diamantane)phosphine. Yield 14.5 g. ³¹P NMR: δ: 42.1 ppm (br).

6.5 Synthesis of 1,2 bis(diamantane phosphor(borane)methyl)benzene viadeprotonation with ^(sec)BuLi and reaction with αα dichloro o-xylene.Prepared as per 1,2 bis(di-1-adamantylphosphor(borane)methyl)benzeneexcept using an equimolar amount of diamantane phosphine trihydroboroninstead of di-1-adamantyl phosphine trihydroboron.

6.6 Synthesis of 1,2 bis(diamantanephosphinomethyl)benzene viadeprotection of 1,2 bis(diamantane(borane)methyl)benzene withHBF₄.O(ME)₂. Prepared as per 1,2 bis(di-1-adamantylphosphinomethyl)benzene except using an equimolar amount of 1,2 bis diamantinephosphor(borane)methyl)benzene instead of 1,2bis(di-adamantylphosphor(borane)methyl)benzene.

Example 7

Preparation of 1,2-bis-(ditertbutylphosphinomethyl)benzene

The preparation of this ligand was carried out in the manner disclosedin WO 99/47528 in accordance with Example 18.

Example 8 (Comparative)

Preparation of 1,3 bis(diadamantylphosphino)propane

Preparation of 1,3-bis-(di-1-adamantylphosphino)propane (2)

8.1 Preparation of (1-Ad)₂PLi

Bu^(n)Li (2.5 M in hexanes, 42.02 cm³, 105.1 mmol) was added dropwisevia syringe to a stirred solution of Ad₂PH (10.59 g, 35.0 mmol) in THF(150 cm³). This resulted in a darkening of the solution to yellow andthe precipitation of a large quantity of yellow solid, in a mildlyexothermic reaction. The reaction was stirred at ambient temperature for3 h. The volatiles were removed in-vacuo, affording a very pale orangesolid. The solid was washed with pentane (2×50 cm³) to remove excessBu^(n)Li, resulting in the isolation of a white powder (washings orange)which was dried in-vacuo. The yield for this step was assumed to bequantitative, on the basis of previous NMR experiments.

8.2 Reaction of 1,3-dibromopropane with 2 equiv (1-Ad)₂PLi

1,3-dibromopropane (degassed, 1.78 cm³, 17.5 mmol) was added dropwisevia syringe to a stirred suspension of Ad₂PLi (35.0 mmol, prepared asabove) in THF (150 cm³). Initially a yellow solution was formed, then agreat deal of white solid crashed out (product). The volatiles wereremoved in-vacuo and dichloromethane (300 cm³) added via cannulaaffording a turbid solution. The turbidity was lost on addition of water(degassed, 100 cm³), a two phase system being formed. The lower phasewas removed via cannula filtration. The volatiles were removed in-vacuo,affording a white powder, which was washed with pentane (100 cm³), driedand isolated in the glovebox. Yield 6.45 g, 57%. ³¹P NMR: δ=24 ppm, 95+%pure. FW=644.94.

Example 9

Preparation of 1,2-bis-(dimethylaminomethyl)ferrocene

n-Butyllithium (Aldrich, 2.5 molar in hexane, 24 ml, 54 mmol) is addedto a solution of (dimethylaminomethyl)ferrocene (Aldrich, 13.13 g, 10.69ml, 48.97 mmol) in diethyl ether (80 ml) under nitrogen at a temperatureof 25° C. and the reaction mixture stirred for 4 hours. The resultingred solution is then cooled to approximately −70° C. in a dryice/acetone bath and Eschenmosers salt (ICH₂NMe₂) (Aldrich, 10 g, 54mmol) is added. The reaction is allowed to warm to room temperature andstirred overnight.

The resultant solution is quenched with excess aqueous sodium hydroxideand the resulting product extracted with diethyl ether (3×80 ml) driedover anhydrous magnesium sulfate, filtered over celite, and volatilesremoved in vacuo to yield the crude title compound as a light orangecrystalline solid. The crude product is recrystallised from light petrolwith cooling to −17° C. and the recrystallised product washed with coldpetrol to yield the title compound as a light orange solid (13.2 g,74%). The compound can be further purified by sublimation to give 8.5 g(52%) of the title compound (mpt 74° C.).

¹H NMR (250 MHz; CDCl₃): δ4.23 (brd, 2H); 4.11-4.10 (t, 1H); 4.04 (s,5H); 3.43, 3.38, 3.23, 3.18 (AB quartet, 2H); 2.22 (s, 6H).

¹³C NMR (63 MHz; CDCl₃): δ83.81; 70.40; 69.25; 66.84; 57.35; 45.23.

Elemental analysis: Found: C, 63.7%; H, 8.9%; N, 9.5%.

Calculated: C, 64.0%; H, 8.1%; N, 9.4%.

Example 10

Preparation of 1,2-bis-(ditertbutylphosphinomethyl)ferrocene

Di-tertbutylphosphine (Aldrich, 0.616 ml, 3.33 mmol) was added to asolution of 1,2-bis(dimethylaminomethyl)ferrocene (Example 9, 0.5 g,1.66 mmol) in anhydrous acetic acid (100 ml) under nitrogen and theresulting mixture is stirred at 80° C. for 72 hours. The anhydrousacetic acid is removed in vacuo at approximately 70° C. to yield thecrude title product as an orange/yellow solid. The crude product isrecrystallised from ethanol with cooling to −17° C., filtered and thefiltrate washed with cold ethanol to yield the title compound as a paleyellow solid (0.365 g, 44%, 84° C.).

¹H NMR (250 MHz; CDCl₃): δ4.4 (2H, d, J=2 Hz); 3.95 (5H, S); 3.75 (1H,t, 2 Hz); 2.8 (2H, dd, 12 Hz, 2 Hz); 2.6 (2H, dd, 12 Hz, 2 Hz); 1.1(36H, m).

¹³C NMR (63 MHz; CDCl₃): δ86.73 (d, 5.46 Hz); 70.08 (d, 4.41 Hz);69.4665 (s); 63.75 (s); 31.80 (d, 2 Hz); 31.45 (d, 1.98 Hz); 29.89 (d,1.88 Hz).

³¹P NMR (101 MHz; CDCl₃): δ15.00 ppm.

Elemental analysis: Found: C, 66.79%; H, 9.57%.

Calculated: C, 66.93%; H, 9.63%.

Example 11

Preparation of 1-hydroxymethyl-2-dimethylaminomethyl ferrocene

n-Butyl lithium (Aldrich, 1.6 molar in diethyl ether, 5.14 ml, 8.24mmol) is added to a solution of 1-dimethylaminomethyl ferrocene(Aldrich, 1.0 g, 4.12 mmol) in diethyl ether (20 mL) under argon. Thereaction is stirred for 3 hours and develops a reddish colour. Thesolution is then cooled in a dry ice/acetone bath, calcinedpara-formaldehyde (0.247 g, 2 times excess) added and the resultantmixture stirred overnight at room temperature.

The reaction is then quenched with water, extracted with diethyl ether,dried over MgSO₄, and filtered over celite. The solvent is removed invacuo to yield crude title compound. The crude product is applied to aneutral alumina column, which is eluted with petrol/diethyl ether (9:1ratio) to remove the starting material, 1-dimethylaminomethyl ferrocene.The column is then eluted with substantially pure ethyl acetate to elutethe title compound. The ethyl acetate is removed in vacuo, to yield thetitle compound as an orange oil/crystalline mass.

¹H NMR (250 MHz; CDCl₃) δ2.131 (s, 6H), δ2.735 (d, 1H, 12.512 Hz),δ3.853 (d, 1H, 12.512 Hz), δ3.984 (dd, 1H, 2.156 Hz), δ4.035 (s, 5H),δ4.060 (dd, 1H, 2.136 Hz) δ4.071 (d, 1H, 12.207 Hz), δ4.154 (m, 1H),δ4.73 (d, 1H, 12.207 Hz).

¹³C NMR (61 MHz; CDCl₃) δ7.688, δ84.519, δ70.615, δ68.871, δ68.447,δ865.369, δ60.077, δ58.318, δ44.414

COSY 2D ¹H NMR

Partly obscured doublet at 4.071 ppm and its coupling to the doublet at4.73 ppm confirmed.

Infrared spectra (CHCl₃) (c.a. 0.06 g/0.8 mL)

2953.8 cm⁻¹, 2860.6 cm⁻¹, 2826.0 cm⁻¹, 2783.4 cm⁻¹, 1104.9 cm⁻¹

Example 12

Preparation of 1,2-bis-(ditertbutylphosphinomethyl)ferrocene

Di-tertbutylphosphine (Aldrich, 0.54 ml, 2.93 mmol) is added to asolution of 1-hydroxymethyl-2-dimethylaminomethyl ferrocene (Example 11,0.2 g, 0.753 mmol) in anhydrous acetic acid (15 ml) and acetic anhydride(0.753 mmol) under argon and the resulting mixture is stirred at 80° C.for 72 hours. The anhydrous acetic acid is removed in vacuo atapproximately 70° C. to yield the crude title product as anorange/yellow solid. The crude product is recrystallised from ethanolwith cooling to −17° C., filtered and the filtrate washed with coldethanol to yield the title compound as an orange solid (0.23 g)

¹H NMR (250 MHz; CDCl₃) δ4.351 (d, 2H, 2 Hz), δ4.022 (s, 5H), δ3.827 (t,1H, 2 Hz), δ2.858 (ddd, 2H, J_(HH) 15.869 Hz, J_(HP1) 3.320 Hz, J_(HP2)1.831 Hz), δ2.679 (dd, 2H, J_(HH) 15.869 Hz, J_(HP) 2.441 Hz), δ1.166(d, 18H, 12.817 Hz), δ1.123 (d, 18H, 12.512 Hz)

FTIR (Chloroform, NaCl plates)

1104.1 cm⁻¹, 2863 cm⁻¹, 2896.0 cm⁻¹, 2940.0 cm⁻¹, 2951.8 cm⁻¹

³¹P NMR (101 MHz; CDCl₃): δ15.00 ppm.

Elemental analysis: Found: C, 66.5%; H, 9.6%.

Calculated: C, 66.9%; H, 9.6%.

Example 13

Preparation of 1-hydroxymethyl-2,3-bis-(dimethylaminomethyl)ferrocene

To a stirred solution of 1,2-bis-(dimethylaminomethyl) ferrocene(Example 9, 0.70 g, 2.32 mmol) in diethyl ether (15 cm³) under argon isadded 1.2 equivalents n-butyl lithium (Aldrich, 1.75 mL, 1.6M in diethylether) and the mixture stirred for three hours to yield a red solution.The reaction mixture is cooled in a dry ice/acetone bath, calcinedparaformaldehyde added in 2:1 excess, and the resultant mixture stirredat room temperature overnight. The mixture is quenched with water andextracted with diethyl ether. The ethereal extracts are dried overMgSO₄, filtered over celite and the solvent removed in vacuo, to yieldthe title compound (0.7 g, 2.12 mmol, 91%) as an orange oil., whichpartially crystallized on cooling.

¹H NMR (250 MHz; CDCl₃) δ 2.133 (s, 6H), δ 2.171 (s, 6H), δ 2.910 (d,1H, 12.817 Hz), δ 2.998 (d, 1H, 12.512 Hz), δ 3.425 (d, 1H, 12.817 Hz),δ 3.812 (d, 1H, 12.512 Hz), δ 3.962 (s, 5H), δ 3.99 (d, 1H, 12.207 Hz)(partly obscured by large cp-ring peak at δ 3.962), δ 4.068 (d, 1H,δ2.136 Hz), δ 4.125) d, 1H, δ 2.136 Hz), δ 4.747 (d, 1H, 12.207 Hz)

¹³C NMR (60 MHz; CDCl₃) δ44.529, δ45.244, δ55.798, δ57.906, δ60.271,δ67.944, δ68.277, δ69.612, δ84.850, δ88.322

Infrared spectra (CDCl₃/thin film NaCl plates)

3380.6 cm⁻¹ (br), 2955.7 cm⁻¹ (m), 2862.6 cm⁻¹, 2825.9 cm⁻¹ (m), 2774.3cm⁻¹ (m), 1353.5 cm⁻¹ (m), 1104.9 cm⁻¹ (m), 1038.9 cm⁻¹ (m), 1006.8 cm⁻¹(s)

Elemental analysis: Found: C, 62.3%; H, 7.8%; N, 8.8%.

Calculated: C, 61.8%; H, 7.9%; N, 8.5%.

Example 14

Preparation of 1,2,3-tris-(ditertbutylphosphinomethyl)ferrocene

Di-tert-butylphosphine (Aldrich, 2.60 mL, 13.98 mmol) and aceticanhydride (0.24 mL, 2.33 mmol) is added to a solution of1-hydroxymethyl-2,3-bis-(dimethylaminomethyl)ferrocene (Example 13, 0.70g, 2.12 mmol) in acetic acid (freshly distilled from acetic anhydride 25cm³), under argon. The solution is then stirred at 80° C. for 7 days,during which time the solution becomes a dark orange colour. The solventis then removed in vacuo and recrystallisation effected from refluxingethanol together with cooling to −17° C. overnight to yield the titlecompound (0.43 g, 0.7 mmol, 31%) as a yellow/orange powder.

¹H NMR (250 MHz, CDCl₃) δ 1.12 (dd-pseudo triplet, 36H, 12.1 Hz), δ1.26(d, 18H, 10.7 Hz), δ2.68 (d, 2H, 17.7 Hz), δ2.95 (s, 2H), δ3.07, (m,2H), δ4.01 (s, 5H) δ 4.33 (s, 2H)

Infrared spectra (CHCl₃/thin film NaCl plates)

1365.5 cm⁻¹, 1470.3 cm⁻¹, 2357.1 cm⁻¹, 2862.8 cm⁻¹, 2896.7 cm⁻¹, 2939.1cm⁻¹

Example 15

Preparation of 1,2-bis-(dicyclohexylphosphinomethyl)ferrocene

The title compound was prepared in accordance with the procedure ofExample 10 employing dicyclohexylphosphine (Strem of 48 High StreetOrwell, Royston, United Kingdom SG8 5 QW, 659 mg, 3.33 mmol),1,2-bis(dimethylaminomethyl)ferrocene (0.5 g, 1.66 mmol) and anhydrousacetic acid (100 ml). Yield 0.421 g.

Example 16

Preparation of 1,2-bis-(di-iso-butylphosphinomethyl)ferrocene

The title compound was prepared in accordance with the procedure ofExample 10 employing di-iso-butylphosphine (Strem 486 mg, 3.33 mmol),1,2-bis(dimethylaminomethyl)ferrocene (0.5 g, 1.66 mmol) and anhydrousacetic acid (100 ml). Yield 0.372 g.

Example 17

Preparation of 1,2-bis-(dicyclopentylphosphinomethyl)ferrocene

The title compound was prepared in accordance with the procedure ofExample 10 employing dicyclopentylphosphine (Strem 566 mg, 3.33 mmol),1,2-bis(dimethylaminomethyl)ferrocene (0.5 g, 1.66 mmol) and anhydrousacetic acid (100 ml). Yield 0.432 g.

Example 18

Preparation of 1,2-bis-(diethylphosphinomethyl)ferrocene

The title compound was prepared in accordance with the procedure ofExample 10 employing diethylphosphine (Strem 299 mg, 3.33 mmol),1,2-bis(dimethylaminomethyl)ferrocene (0.5 g, 1.66 mmol) and anhydrousacetic acid (100 ml). Yield 0.254 g.

Example 19

Preparation of 1,2-bis(di-isopropylphosphinomethyl)ferrocene

The title compound was prepared in accordance with the procedure ofExample 10 employing di-iso-propylphosphine (Digital SpecialityChemicals 392 mg, 3.33 mmol), 1,2-bis(dimethylaminomethyl)ferrocene (0.5g, 1.66 mmol) and anhydrous acetic acid (100 ml). Yield 0.262 g.

Example 20

Preparation of 1,2-bis-(dimethylphosphinomethyl)ferrocene

The title compound was prepared in accordance with the procedure ofExample 10 employing dimethylphosphine (Digital Speciality Chemicals,206 mg, 3.33 mmol), 1,2-bis(dimethylaminomethyl)ferrocene (0.5 g, 1.66mmol) and anhydrous acetic acid (100 ml). Yield 0.285 g.

Example 21

Preparation of1,2-bis-(diadamantylphosphinomethyl)ferrocene-bis-methanesulphonate

Di-adamantylphosphine (prepared according to J. R. Goerlich, R.Schmutzler; Phosphorus Sulphur and Silicon; 1995, 102, 211-215, 20.0 g,0.066 mol) was added to a solution of1,2-bis(dimethylaminomethyl)ferrocene (Example 9, 10 g, 0.033 mol) inanhydrous acetic acid (100 ml) under nitrogen and the resulting mixtureis stirred at 80° C. for 72 hours. The orange yellow precipitate whichforms is filtered and dried in vacuo at approximately 70° C. to yieldthe title compound as an orange/yellow solid. The title compound isinsoluble in a range of organic solvents and it is therefore purified byconversion to the bis-methanesulphonate salt by addition of excessmethanesulphonic acid to a methanol slurry of the crude product. Thisresulted in complete dissolution of the product salt which was thenisolated by removal of the methanol in vacuo followed by washing withether and drying to give the title compound as a pale yellow solid (14.0g, 54%).

¹H NMR (250 MHz; CD₃CN): δ4.57 (2H, d, J=2 Hz); 4.35 (5H, S); 4.27 (1H,t, 2 Hz); 3.34 (4H, br); 2.6 (6H, br); 2.35-2.18 (18H br); 2.16-2.0(18H, br); 1.92-1.72 (24H, br).

³¹P NMR (101 MHz; CD₃CN): δ26.58 ppm.

Elemental analysis: Found: C, 64.15%; H, 7.88%. Calculated: C, 64.29%;H, 7.94%.

Example 22

Preparation of 1,2bis(di-1-adamantylphosphinomethyl)ferrocene-bis-methane sulphonate

The preparation of this ligand was carried out as follows:

22.1 Preparation of (1-Ad)₂P(O)Cl

The di-1-adamantyl phosphine chloride was prepared in accordance withthe method of Example 1.1.

22.2 Preparation of (1-Ad)₂PH

The di-1-adamantyl phosphine was prepared in accordance with the methodof Example 1.2.

22.3 Preparation of1,2-bis(di-1-adamantylphosphinomethyl)ferrocene-bis-methanesulphonate

The title compound was prepared in accordance with the procedureexemplified in Example 21.

Example 23

Preparation of1,2-bis(di-1-(3,5-dimethyladamantyl)phosphinomethyl)ferrocene-bis-methanesulphonate

23.1 Di-1-(3,5-dimethyladamantyl)phosphinic chloride was prepared inaccordance with the method of Example 3.1.

23.2 Di-1-(3,5-dimethyladamantyl)phosphine was prepared in accordancewith the method of Example 3.2.

23.3 1,2-bis-(di-1-(3,5-dimethyl-adamantylphosphinomethyl)ferrocene-bis-methanesulphonate

The title compound was prepared in accordance with the procedureexemplified in Example 21 except usingdi-1-2(3,5-dimethyl-adamantyl)phosphine (23.69 g, 0.066 mol) instead ofdi-adamantylphosphine. Yield 15 g.

Example 24

Preparation of1,2-bis(di-1-(5-tert-butyl-adamantyl)phosphinomethyl)ferrocene-bis-methanesulphonate

24.1 Di-1-(5-tert-butyladamantyl)phosphinic chloride was prepared as perExample 4.1 above.

24.2 Di-1-(5-tert-butyladamantyl)phosphine was prepared as per Example4.2 above.

24.31,2-bis(di-1-(4-tert-butyl-adamantyl)phosphinomethyl)ferrocene-bis-methanesulphonate

The title compound was prepared in accordance with the procedureexemplified in Example 21 except usingdi-1-(4-tert-butyladamantyl)phosphine (27.39 g, 0.066 mol) instead ofdi-adamantyl phosphine. Yield 14.52 g.

Example 25

Preparation of 1,2-bis-(1-adamantyltert-butyl-phosphinomethyl)ferrocene-bis-methanesulphonate

25.1 1-adamantylphosphonic acid dichloride

This compound was synthesised according to the method of Olah et al (J.Org. Chem. 1990, 55, 1224-1227).

25.2 1-adamantyl phosphine

LiAlH₄ (3.5 g, 74 mmol) was added over 2 hours to a cooled solution (0°C.) of 1-adamantylphosphonic acid dichloride (15 g, 59 mmol) in THF (250cm³). The reaction was then allowed to warm to ambient temperature andwas stirred for 20 hours. The grey suspension was then cooled (0° C.)and HCl (75 cm³, 1M) was slowly added via syringe, to afford a two phasesystem with some solid present in the lower phase. Concentrated HCl (8cm³, 11M) was then added to improve the separation of the two layers.The (upper) THF phase was removed via cannula and dried over magnesiumsulphate. After filtration via cannula, the volatiles were removedin-vacuo to afford the product.

25.3 1-adamantyl tert-butyl phosphine

nBuLi (20 cm³, 32 mmol 1.6M soln) was added over 1 hour to a cooledsolution of 1-adamantyl phosphine (5.0 g, 30 mmol) in THF (100 cm³). Thesolution was allowed to warm to room temperature and stirred for afurther 2 hours. The solution was recooled to 0° C. andtert-butylchloride (2.78 g, 30 mmol) was added and stirring continuedfor a further 16 hours at room temperature. The reaction mixture wasquenched with water and the aqueous phase extracted with dichloromethane(2×50 ml). The organic phase was dried over sodium sulphate andevaporated in-vacuo to yield the title compound.

25.4 1,2-bis-(-1-adamantyltert-butyl-phosphinomethyl)ferrocene-bis-methanesulphonate

The title compound was prepared in accordance with the procedureexemplified in Example 21 except using 1-adamantyl tert-butyl phosphine(14.78 g, 0.066 mol) instead of di-adamantyl phosphine. Yield 9.80 g.

Example 26

Preparation of1,2-bis-(di-1-diamantylphosphinomethyl)ferrocene-bis-methanesulphonate

26.1 Diamantane

This was synthesised according to the method of Tamara et al. OrganicSyntheses, CV 6, 378.

26.2 Di-1-(diamantane)phosphinic chloride

Prepared as per Di-1-adamantyl phosphinic chloride of Example 1.1 exceptusing diamantane 20.0 g (0.106 mol) and AlCl₃ (16.0 g, 0.12 mol). Yield25.5 g FW: 456.5. ³¹P NMR: δ: 87 ppm (s).

26.3 Di-1-(diamantane)phosphine

Prepared as per Di-1-adamantyl phosphine of Example 1.2 except using25.0 g Di-1-(diamantane)phosphinic chloride. Yield 14.0 g FW: 406. ³¹PNMR: δ: 16.5 ppm (s).

26.41,2-bis-(di-1-diamantylphosphinomethyl)ferrocene-bis-methanesulphonate

The title compound was prepared in accordance with the procedureexemplified in Example 21 except using di-1-diamantane phosphine (26.79g, 0.066 mol) instead of di-adamantyl phosphine. Yield 12.5 g.

Example 27

Preparation of1,2-bis-(di-(1,3,5,7-tetramethyl-6,9,10-trioxa-2-phospha-adamantylmethyl))ferrocene

1,3,5,7-tetramethyl-2,4,8-trioxa-6-phospha-adamantane (obtained fromCytec, 14.0 g, 0.066 mol) was added to a solution of1,2-bis(dimethylaminomethyl)ferrocene (Example 9, 10 g, 0.033 mol) inanhydrous acetic acid (100 ml) under nitrogen and the resulting mixtureis stirred at 80° C. for 72 hours. The anhydrous acetic acid is removedin vacuo at approximately 70° C. to yield the crude title product as anorange/yellow solid. This is washed with hot methanol to give theproduct as a mixture of isomers as an orange solid. (12.0 g, 58%).

1H NMR (250 MHz; CDCl₃): δ4.25-3.95 (8H, br, m); 3.46 (4H, br); 1.57-2.0(8H, br, m); 1.43-1.23 (24H, br m).

³¹P NMR (101 MHz; CDCl₃): δ −27.41 (br), −29.01 (s), −33.9 (br) ppm.

Elemental analysis: Found: C, 57.80%; H, 7.35%. Calculated: C, 57.87%;H, 7.40%.

Example 28

Preparation of 1,2-bis-(dimethylaminomethyl)ferrocene-bis methyl iodide

Methyl iodide (23.28 g, 0.164 mol) is added to a solution of1,2-bis-(dimethylaminomethyl)ferrocence (Example 9, 20 g, 0.082 mol) indegassed methanol (100 ml), and the mixture stirred at room temperatureunder a nitrogen atmosphere for 24 hours. The resulting precipitate isremoved by filtration, washed with ether and dried to yield the titlecompound (43.0 g).

Elemental analysis: Found: C, 36.8%; H, 5.1%; N, 4.8%.

Calculated: C, 37.0%; H, 5.2%; N, 4.8%.

¹³C NMR (D₂O): δ53.27, δ53.21, δ53.15, δ64.68, δ71.77, δ73.24, δ74.13,δ74.95

Example 29

Preparation of 1,2-bis(dihydroxymethylphosphinomethyl)ferrocene

Potassium hydroxide (8.52 g, 0.152 mol) is added to a solution oftetrakis(hydroxymethyl)phosphonium chloride (Aldrich, 38.54 g of 80% w/waqueous solution, 0.162 mol) in degassed methanol (40 ml), and stirredat room temperature under a nitrogen atmosphere for 1 hour. Theresultant mixture is added dropwise to a degassed solution of1,2-bis-(dimethylaminomethyl)ferrocene-bis-methyl iodide (Example 28,19.98 g, 52.2 mmol) in methanol (40 ml) under nitrogen at roomtemperature with stirring. The resultant mixture is refluxed undernitrogen for 20 hours, and the solvent removed in vacuo to form a redprecipitate. Water (30 ml), diethyl ether (85 ml) and triethylamine (35ml) is added to the precipitate and the solution stirred at roomtemperature for 1 hour. The aqueous layer is removed and re-extractedwith diethyl ether (2×30 ml). The combined ethereal extracts are washedwith water (3×20 ml) dried over sodium sulphate and filtered. The etheris removed in vacuo to yield the crude title compound (14.33 g, 94%yield) as a microcrystalline orange solid. The crude product isrecrystallised from a warm dicholormethane/methanol solution with theaddition of light petroleum and cooling to yield the title compound(10.69 g, 70% yield) as yello-orange crystals.

Elemental analysis: Found: C, 48.44%; H, 4.12%; N, 0.0%.

Calculated: C, 48.24%; H, 4.02%; N, 0.0%.

¹H NMR: δ1.75 (s, br), δ2.70 (dd, 2H, J² _(HH) 14.2 Hz, J² _(HP) 6.6Hz), δ2.85 (dd, 2H, J² _(HH) 14.2 Hz, J² _(HP) 7.9 Hz), δ3.71 (t, 1H,J_(HH) 2.44 Hz), δ3.58 (s, 5H), δ3.98 (d, 2H, J_(HH) 2.40 Hz), 4.06 (m,8H).

¹H{³¹P} NMR: δ1.75 (s, br), δ2.70 (d, 14.3 Hz), δ2.85 (d, 14.3 Hz),δ4.04 (m, 1H), δ4.06 (s, 8H), δ4.08 (s, 5H), δ4.1 (m, 2H)

¹³C NMR: 523.7 (d, J¹ _(PC) 15.6 Hz), δ63.0 (d, J¹ _(PC) 15.6 Hz), δ66.0(s), δ67.2 (d, J³ _(PC) 9.2 Hz), δ69.6 (s), δ82.6 (d, J² _(PC) 14.7 Hz)

³¹P NMR: δ−14.7

Infrared spectra (CHCl₃/thin film NaCl plates)

3337.8 cm⁻¹ (st, br), further peaks 1104 cm⁻¹ 2929.0 cm⁻¹, 3603.7 cm⁻¹,3683.7 cm⁻¹.

Example 30

Preparation of 1,2-bis(diphosphinomethyl)ferrocene

1,2-bis(dihydroxymethylphosphinomethyl)ferrocene (Example 29, 5.45 g,13.70 mmol) and sodium metabisulfite (5.21 g, 27.4 mmol) is added to atwo-phase solvent system consisting of distilled water (60 ml) and lightpetroleum (60 ml). The mixture is refluxed for 3 hours in air. Theresultant mixture is cooled stirred and the aqueous layer removed. Theorganic layer is washed with distilled water and the organic solventremoved in vacuo to yield the title compound (2.66 g, 70% yield) as anorange crystalline solid.

Elemental analysis: Found: C, 51.65%; H, 5.75%.

Calculated: C, 51.80%; H, 5.76%.

¹H NMR (250 MHz; CDCl₃): δ 2.7-2.8 (m, 4H), δ 3.17 (m, 2H), δ 3.18 (m,2H), δ 4.04 (t, 1H, J=2.54 Hz), δ 4.09 (d, 5H, J_(HP) 0.4 Hz), δ 4.13(d, 2H, J=2.54 Hz)

³¹P NMR (101 MHz; CDCl₃): δ130.0 (t, J_(HP) 193.0 Hz)

¹³C NMR (60 MHz; CDCl₃): δ12.9, δ 65.6, δ 67.3, δ 69.4, δ 86.9

¹³C DEPT NMR (CDCl₃): δ 12.9 (CH²), δ 65.6 (CH), δ 67.3 (CH), δ 69.40(5×CH)

FTIR (Chloroform, NaCl plates): 2298.5 cm⁻¹ (strong)

Mass spectrum: Found m/z: 278.0088; Calculated m/z 278.0077

Example 31

Preparation of—(P-(2,2,6,6,-tetramethylphosphinan-4-one))dimethylferroce□,□1,2-bis-ne

2,6-Dimethyl-2,5-heptadiene-4-one (14.6 g, 0.106 mol) is added to1,2-bis-(diphosphinomethyl)ferrocene (Example 30, 14.7 g, 0.053 mol) andthe mixture heated to 120° C. under nitrogen for 20 hours. The reactionmixture is cooled, the crude title compound removed by filtration,washed with pentene (20 ml) and dried in vacuo to yield the titlecompound as a yellow-orange solid (24.9 g, 85% yield). The titlecompound was characterised by ³¹P NMR and mass spectrum.

¹H NMR (250 MHz; CDCl₃): d 4.32 (1H, br); 4.08 (5H, br); 4.02 (1H, br);3.94 (1H br); 2.84 (4H, br); 1.8-2.5 (8H, br); 1.05-1.4 (24H, br).

³¹P NMR (101 MHz; CDCl₃): s 4.15 ppm.

Elemental analysis: Found: C, 64.26%; H, 7.88%.

Calculated: C, 65.03%; H, 7.94%.

Example 32

Preparation of1,2-bis-(di-1,3,5,7-tetramethyl-6,9,10-trioxa-2-phospha-adamantylmethyl))benzene

The preparation of this ligand was carried out in the manner disclosedin WO-A-03/070370 in accordance with Example 4 therein.

Example 33

Preparation of Methyl Propanoate from Ethylene, Carbon Monoxide andMethanol Catalysed by a Compound of the Present Invention

Condition 1 ratio of ligand:palladium=5.2:1, ratio ofacid:palladium=160:1 and ratio acid:ligand=30:1

Condition 2 ratio of ligand:palladium=5.2:1, ratio ofacid:palladium=480:1 and ratio acid:ligand=90:1

A mechanically stirred autoclave (Hastelloy) of 2 liter capacity wasevacuated of air and then charged with a solution oftri(dibenzylideneacetone)dipalladium (1.44×10⁻⁵ moles),1,2-bis-(di-tertbutylphosphinomethyl)ferrocene of Example 10, (7.61×10⁻⁵moles) and methane sulfonic acid (2.30×10⁻³ moles condition 1, 6.90×10⁻³moles condition 2) in 300 ml of methyl propanoate/methanol (70 wt %methyl propanoate). The autoclave was heated to 100° C. and when at thattemperature, ethylene (8×10⁵ Nm⁻²) was added on top of the vapourpressure of the solvents and immediately an equimolar mixture of carbonmonoxide and ethylene (2×10⁵ Nm⁻²) added to the system through apressure regulating valve set to 10×10⁵ Nm⁻² above the solvent vapourpressure. Suitably, the molar ratio of ethylene to carbon monoxide inthe reactor is approximately 9:1. The temperature of the reactor wasmaintained at 100° C. and as the reaction proceeded additional carbonmonoxide and ethylene was added (on an equimolar basis) through thepressure regulating Tescom valve. No catalyst precipitation wasobserved.

Initial reaction rates measured in moles of methyl propanoate (MeP) permole of palladium per hour and turnover measured in moles of methylpropanoate per mole of palladium were determined for the catalyst. Thismay be accomplished by an analysis of the amount of gas consumed perunit time (rate) and the total amount of gas consumed during thereaction, assuming ideal gas behaviour and 100% selectivity to methylpropanoate.

Table 1 shows the effect in increasing the relative acid concentrationcompared to phosphine ligand concentration (and metal concentration) fora batch process on both the maximum initial rate and the turnover number(TON) after 1 hour, wherein initial reaction rates are measured in molesof methyl propanoate (MeP) per mole of palladium per hour and TON ismeasured as moles of methyl propanoate per mole of palladium. For bothTON and maximum initial rate, values are significantly increased passingfrom condition 1 to condition 2, i.e. when increasing both theacid:palladium and acid:ligand ratios at constant ligand:palladiumvalues.

TABLE 1 Maximum Turnover Initial Rate Number after (moles MeP/ 1 hour(moles mole Pd/hr) MeP/mole Pd) 1,2-bis-(di-tert- 66261 50786butylphosphinomethyl)benzene - condition 2 1,2-bis-(di-tert- 42103 32397butylphosphinomethyl)benzene - condition 1 1,2-bis-(di-tert- 94957 62635butylphosphinomethyl)benzene - condition 2 1,2-bis-(di-tert- 45421 29465butylphosphinomethyl)benzene - condition 1 l,2-bis-(di-(1,3,5,7- 5579951997 tetramethyl-6,9,10-trioxa-2-phospha- adamantylmethyl))ferrocene -condition 2 1,2-bis-(di-(1,3,5,7- 8490 4814tetramethyl-6,9,10-trioxa-2-phospha- adamantylmethyl))ferrocene -standard -(P-(2,2,6,6,- 29839 24270 tetramethylphosphinan-4-one))dimethylferroce□□□1,2- bis-ne - condition 2 -(P-(2,2,6,6,- 2159117676 tetramethylphosphinan-4- one))dimethylferroce□□□1,2- bis-ne -condition 1 1,2-bis-(di-(1,3,5,7- 29839 24270tetramethyl-6,9,10-trioxa-2-phospha- adamantylmethyl))benzene -condition 2 1,2-bis-(di-(1,3,5,7- 12041 11444tetramethyl-6,9,10-trioxa-2-phospha- adamantylmethyl))benzene -condition 1 1,2-bis-(di-(1,3,5,7- 20177 16610tetramethyl-6,9,10-trioxa-2-phospha- adamantylmethyl))benzene -condition 2 1,2-bis(di-1- 67599 68141 adamantylphosphinomethyl)ferrocene-bis-methanesulphonate - condition 2 1,2-bis(di-1- 41167 33798adamantylphosphinomethyl) ferrocene-bis-methanesulphonate - condition 1

Example 34

Pd(OAc)₂(22 mg, 0.1 mmol) and the respective phosphine ligand (0.5 mmol)were weighed out in the inert atmosphere glove box into 500 mL 3-neckround bottom flasks. On removal, 300 mL of degassed MeOH were added andthe mixture stirred for 1 hour. To the solution methanesulphonic acid(640 μl, 10 mmol) was added. The weight of the catalyst solution wastaken. The autoclave was charged with the solution and heated to 100 Cwith stirring (3.0 barg vapour pressure). The reaction was started bythe introduction of CO/ethylene (1:1) gaseous mixture to the autoclave.The total pressure of the autoclave was controlled by a TESCOM (9.8barg). This resulted in a 9:1 ratio of ethylene to CO. The temperatureand pressure were maintained 3 hours during which period these valueswere recorded.

The gases were isolated and the unit cooled to room temperature. Thedepressurised unit was emptied and the final weight of the solutiontaken.

Ligand 1=1,2-bis(di-tert-butylphosphinomethyl)benzene

Ligand 2=1,2-bis(di-tert-butylphosphinomethyl)ferrocene

Ligand 3=1,2-bis(diadamantylphosphinomethyl)ferrocene

Ligand 4=1,2-bis(diphospha-adamantylphosphinomethyl)ferrocene

Ligand 5=1,3-bis(di-tert-butylphosphino)2-methylene-propane(comparative), prepared as in WO-A-03/040159 (Example 1 therein).

The results are shown in the tables below.

TABLE 2 Ratio Wt Gain Avg. Wt Ligand Pd:Lig:Acid (g) Gain (g) 1 1:5:100268.65 257.304 1 1:5:100 244.47 1 1:5:100 258.98 1 1:5:100 252.13 11:5:100 262.29

TABLE 3 Ratio Wt Gain Avg. Wt. Ligand Pd:Lig:Acid (g) Gain (g) 2 1:5:100302.64 300.9 2 1:5:100 306.84 2 1:5:100 293.4 2 1:5:100 303.09 2 1:5:100298.54

TABLE 4 Ratio Wt gain Avg Wt Ligand Pd:Lig:Acid (g) Gain (g) 3 1:5:100364.97 347.54 3 1:5:100 340.18 3 1:5:100 345.15 3 1:5:100 339.88

TABLE 5 Ratio Wt gain Avg Wt Ligand Pd:Lig:Acid (g) Gain (g) 4 1:5:25 126.31 Av 1:5:300 4 1:5:100 165.21 249.67 4 1:5:100 189.83 4 1:5:300221.61 4 1:5:300 261.28 4 1:5:300 281.81 4 1:5:300 233.99

TABLE 6 Wt gain Ratio Run No. Ligand (g) Pd:Lig:Acid 1  5 33.3  1:5:1002  5 83.16  1:1:100 3^(a) 5 165.1 1:1:4 4^(a) 5 235.97 1:1:4 5^(a) 582.53 1:6:4 ^(a)run at 3 × palladium concentration {67.3 mg Pd(OAc)₂}

For the ligand 1,3-bis(di-tert-butylphosphino)2-methylene-propane(ligand 5) additional ligand with or without excess acid results in adrop in catalyst performance. The optimum conditions of low ligand andacid, e.g. Run Nos. 3 and 4, result in the highest catalyst productivityunder the conditions studied. Addition of excess ligand at high acidratio as in Run No. 1 results in a significant drop in performance, asdoes addition of excess ligand at low acid ratios.

The following two tables contain data for the ligand1,2-Bis(di-tert-butylphosphinomethyl)benzene. The data was collected at80 C hence the rates and turnover numbers are lower than the data wehave already included. However, the data shows that at constantacid:ligand^(b) levels, an increase in ligand:Pd ratio provides largeincreases in initial rate and TON values. This data also used thepreformed catalyst [(L-L)Pd(dba) (for details see below) and adds theligand excess as the protonated salt. The experimental detail isprovided below.

TABLE 7 Ratio Ratio Initial TON after Ligand Pd:Lig:Acid Acid:Ligand^(b)rate 4 hours 1 1:5:36 10.9 5000 12000 1 1:5:72 20 17000 25000 1  1:5:14337 22000 30000 ^(b)in this ratio the “acid” includes both the acid fromthe protonated phosphine ligand together with the additional acid added(i.e., “free” acid) and the ligand is simply the protonated phosphineligand.

TABLE 8 Ratio Ratio Initial TON after Ligand Pd:Lig:Acid Acid:Ligand^(b)rate 4 hours 1 1:10:90  10.9 22000 42000 1 1:10:182 20 33000 52000 11:10:352 37 41500 71000

The number of moles of palladium is equal to the number of moles ofL₂Pd(dba).

The work described in these examples was carried out in 2 L capacityautoclaves. In each test 10 mg of L₂Pd(dba) catalyst and 32 mg (4equivalents) or 72 mg (9 equivalents) of protonated phosphine were addedto the preparation flask in a nitrogen purged glove box. 175 mL ofazeotrope product consisting of 50:50 wt % methanol and methylpropanoate and 125 mL of methyl propanoate were then degassed and addedto the flask to provide a reaction solution which was close to 70 wt %methyl propanoate. After addition of the required quantity ofmethanesulphonic acid the solution was transferred to the evacuatedautoclave and heated to 80° C. in vacuo. During this period and at allsubsequent times the autoclave was stirred at ˜1000 r.p.m. When thistemperature had been reached the total pressure of the system wasincreased to 9 bar (from the vapour pressure baseline of ˜1 bar) by theaddition of ethylene and then topped up with 2 bar of 1:1 C₂H₄/CO suchthat the total pressure was ˜11 bar and the headspace C₂H₄/CO ratio was9:1. After this time only the 1:1 gas was fed to the system at the ratewhich was required to hold the pressure within the system constant.Reaction rates and catalyst TONs were calculated from the rate ofremoval of gas from the feed reservoir assuming ideal gas behaviour and100% selectivity for methyl propanoate formation.

Preparation of 1,2-bis(di-1-adamantylphosphinomethyl)benzene palladium(dba)

THF (100 cm³) was added to a combination of ligand (2.05 g, 2.90 mmol)and palladium dba (1.61 g, 2.90 mmol [Pd]) affording a deep red-orangeturbid solution. The reaction was stirred for 3 h. The reaction wasfiltered via cannula, yielding a deep red-orange filtrate and a smallquantity of [Pd] residue. The volatiles were removed in-vacuo affordinga deep red powdery solid. Pentane (50 cm³) was added via cannula andattrition performed with a spatula, resulting in an orange powderseparating out. The amber pentane washings were removed via cannulafiltration, and the solid washed with Et₂O at −10° C. (3×50 cm³). Theresultant orange powder was dried in-vacuo and isolated in the glovebox.Yield 2.68 g, 88%. ³¹P NMR: δ=46, 42 ppm (1:1 ratio), essentiallyphosphorus pure. FW=1047.73.

Preparation of 1,3-bis-(di-1-adamantylphosphino)propane palladium (dba)

As above, except using ligand (1.96 g, 3.04 mmol) and palladium dba(1.69 g, 3.04 mmol [Pd]) in THF (70 cm³).

After 3 h, the deep red-orange solution was fairly turbid in appearance;an additional 50 cm³ THF was added to further dissolve the product. Thereaction was worked-up as above, except the Et₂O washing was performedat ambient temperature. The solid was isolated in the glovebox as anorange powder. Yield 2.08 g, 69%. 31P NMR: δ=42, 38 ppm (1:1 ratio,noisy). FW=985.66.

Also see “Studies on the Palladium Catalysed Methoxy-carbonylation ofEthene”, thesis submitted to the University of Durham by G. R. Eastham(1998), for details on the preparation of L₂Pd(dba) complexes.

Example 35

Preparation of Methyl Propanoate from Ethylene, Carbon Monoxide andMethanol Catalysed by a Compound of the Present Invention

The continuous process exemplified involved the reaction of purifiedstreams of carbon monoxide, ethylene and methanol in the liquid phase,in the presence of a catalyst system, to generate the desired product,methyl propanoate.

The reaction was carried out at 100° C. and at 12 barg pressure in thereactor vessel.

The catalyst system was made up of three components, being a palladiumsalt, a phosphine ligand and an acid. The three catalyst components,when combined together and dissolved in the reaction mixture, constitutethe reaction catalyst or catalyst system, a homogeneous catalyst, whichconverted dissolved reactants to the product methyl propanoate in theliquid phase.

During continuous operation, the catalyst decomposed at a slow butsteady rate, and was replaced by adding fresh catalyst, or the rate ofgeneration of the product, methyl propanoate reduces.

The reactor vessel was fitted with an agitator, and also a means ofre-circulating the unreacted gas that collected in the upper headspacearea of the reactor. The unreacted gas from the reactor vesselheadspace, which was made up of a mixture of ethylene and carbonmonoxide, was returned continuously to the reactor via an entry pipe atthe base, such that the gas passed up through the reaction mixturecontinuously.

Upon entering into the reactor vessel the gas was dispersed by theagitator into fine bubbles. In this way the ethylene and carbon monoxidewere dissolved in the reaction mix.

Fresh ethylene and carbon monoxide gases were added to there-circulating gas to make up for the amount of the two gases that havebeen used up by the reaction. Fresh methanol was also added continuouslyto the reactor vessel, in order to replace the methanol that has beenused up in the reaction.

The reactor vessel held the bulk liquid reaction mixture, along with thethree components of the homogeneous catalyst, being a palladium salt, aphosphine ligand, and a sulphonic acid.

In order to recover the product methyl propanoate, a stream of reactionmixture was passed continuously out of the reactor and into thedistillation column.

The distillation column, being a single stage ‘flash’ type distillationcolumn, provided a means of separating a fraction of the methylpropanoate and methanol components of the reaction mixture from thenon-volatile dissolved catalyst components. This was achieved byvaporising a fraction of the reaction mixture as it passed through theflash column. The part of the reaction mixture which remained as liquidafter passing through the flash column, and which still contained usefulcatalyst components, was returned to the reactor vessel so that thecatalyst components could take part in the on-going reaction.

If the methyl propanoate product was required free of methanol, a seconddistillation column was required. In this case, the vapour stream fromthe flash column, which is a mixture of methyl propanoate and methanolwas passed into the second distillation column, where the pure methylpropanoate was generated as the heavier product, and taken off from thebase of the column. A low boiling mixture of methanol and methylpropanoate was generated as the light product, and was removedcontinuously from the top of the MeP purification column. In order toutilise the methanol as efficiently as possible in the process, the lowboiling mixture of methanol and methyl propanoate was returnedcontinuously to the reactor vessel.

After start up of the continuous reactor unit, when the desired rate ofgeneration of methyl propanoate had been achieved, a process of gradualreduction of the feed rates of the catalyst components was undertaken.

In order to sustain the rate of generation of methyl propanoate it wasnecessary to continuously replace the palladium catalyst component whichwas lost to decomposition with fresh palladium at a rate which balancedthe rate of loss.

This led to the situation where the standing concentrations of catalystcomponents became constant for a given rate of generation of methylpropanoate, and just able to sustain flow sheet reaction rate, asindicated by constant concentrations of carbon monoxide and ethylene inthe headspace area of the reactor vessel. This was called the balancepoint, because under these conditions the rate of palladiumdecomposition was balanced exactly by the rate of addition of freshpalladium.

From the rate of addition of fresh palladium catalyst component underbalance point conditions, the palladium turnover number (TON) wascalculated. This is defined as the number of mol of methyl propanoategenerated per hour, for each mol of palladium consumed by thedecomposition process per hour.

Upon reaching a steady rate at a pre-determined set of controlconditions, the instantaneous values of all of the variables wererecorded, and used as representative data to show the performance of theprocess under the conditions in use at the time.

To gather data on the effect of levels of phosphine ligand and acidpresent in the reaction mixture on palladium turnover number, allvariables were held constant except the background levels of ligand andacid in the reaction mixture. These levels were changed by making smalladditions of these compounds to the reaction vessel via a dedicated tankand pumping system. The additions were then followed by carefuladjustment of the catalyst solution feed rate to re-establish thebalance position.

The experimental design was such that after collecting each new set ofbalance point data, the system was returned to a previous set ofconditions to check for any drifting of performance before moving on tothe next set of experimental conditions.

In this way, comparative sets of results were drawn up which showedclearly the changes to catalyst stability that were caused by thevariations in the background levels of phosphine ligand and acid levels.

The amount of palladium in the feed to the reactor is critical tocalculation of turnover number results. Assurance on the rate of freshcatalyst being fed to the system was provided by analysis of each batchof catalyst prior to transfer to the catalyst feed tanks for palladiumcontent. Further assurance was gained by determination of the actualfeed rate of catalyst from timing of the fall in the level in a burette,which is part of the catalyst feed system.

Table 9 shows the effect on palladium turnover number (TON) whenincreasing the acid:ligand ratio and the ligand:metal ratio.

In this Example, the acid used was methanesulphonic acid, the bidentatephosphine ligand was 1,2-bis-(ditertbutylphosphinomethyl)benzene, andthe palladium compound was tri(dibenzylideneacetone)dipalladium.

TABLE 9 ligand:Pd acid:ligand Free acid in Turnover Number mol ratio molratio reactor (ppm) (moles MeP/moles Pd) 6.29 9.93 676 2.02 × 10⁶ 10.3313.38 988 3.30 × 10⁶ 13.49 21.73 1682 3.41 × 10⁶ 17.16 34.65 2834 3.42 ×10⁶ 17.16 7.40 837 5.00 × 10⁶

Further trends are seen in FIG. 1-3 of the accompanying figures.

FIG. 1 shows TON versus acid:ligand mol ratio. Clearly, as theacid:ligand ratio increases above about 10, there is a large increase inTON for this particular catalyst system.

FIG. 2 shows TON versus amount of methanesulphonic acid present free inthe reactor. Clearly, as the level of acid increases, there is a largeincrease in TON for this particular catalyst system.

FIG. 3 shows Pd amount in solution versus amount of methanesulphonicacid. Clearly, as the level of acid increases, there is a decrease inthe amount of Pd in solution for this particular catalyst system, whilstthe reaction rate remains constant. Therefore, working at these elevatedacid levels, reaction rates can be maintained even as the palladiumlevels decrease. The advantages in view of the relative cost of thepalladium component of the catalyst system is clear.

Although some preferred embodiments have been shown and described, itwill be appreciated by those skilled in the art that various changes andmodifications might be made without departing from the scope of thepresent invention, as defined in the appended claims.

Attention is directed to all papers and documents which are filedconcurrently with or previous to this specification in connection withthis application and which are open to public inspection with thisspecification, and the contents of all such papers and documents areincorporated herein by reference.

All of the features disclosed in this specification (including anyaccompanying claims, abstract and drawings), and/or all of the steps ofany method or process so disclosed, may be combined in any combination,except combinations where at least some of such features and/or stepsare mutually exclusive.

Each feature disclosed in this specification (including any accompanyingclaims, abstract and drawings) may be replaced by alternative featuresserving the same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

The invention is not restricted to the details of the foregoingembodiment(s). The invention extends to any novel one, or any novelcombination, of the features disclosed in this specification (includingany accompanying claims, abstract and drawings), or to any novel one, orany novel combination, of the steps of any method or process sodisclosed.

The invention claimed is:
 1. A process for the carbonylation of anethylenically unsaturated compound comprising contacting ethene withcarbon monoxide and a hydroxyl group containing compound in the presenceof a catalyst system, which system is obtained by combining: a)palladium or a compound thereof, b) a bidentate phosphine, arsine, orstibine ligand, and c) an acid, wherein said ligand is present in atleast a 2:1 molar excess compared to said palladium metal or saidpalladium metal in said metal compound, and said acid is present in atleast a 2:1 molar excess compared to said ligand.
 2. A process asclaimed in claim 1 wherein the ratio of said ligand to said metal is inthe range 5:1 to 750:1.
 3. A process as claimed in claim 1 wherein theratio of said ligand to said metal is in the range 10:1 to 500:1.
 4. Aprocess as claimed in claim 1 wherein the ratio of said ligand to saidmetal is in the range 20:1 to 40:1.
 5. A process as claimed in claim 1wherein the ratio of said acid to said ligand is in the range 20:1 to40:1.
 6. A process as claimed in claim 1 wherein the molar ratio of saidacid to said metal is in the range 10:1 to 75000:1.
 7. A process asclaimed in claim 1 wherein the molar ratio of said acid to said metal isin the range 100:1 to 25000:1.
 8. A process as claimed in claim 1wherein the molar ratio of said acid to said metal is in the range 200:1to 400:1.
 9. A process as claimed in claim 1 wherein said ligand is abidentate phosphine ligand.
 10. A process as claimed in claim 1 whereinsaid ligand is of general formula (I)

wherein: Ar is a bridging group comprising an optionally substitutedaryl moiety to which the phosphorus atoms are linked on availableadjacent carbon atoms; A and B each independently is lower alkylene; K,D, E and Z are substituents of the aryl moiety (Ar) and eachindependently is hydrogen, lower alkyl, aryl, Het, halo, cyano, nitro,OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁵R²⁶, C(S)R²⁵R²⁶,SR²⁷, C(O)SR²⁷, or -J-Q³(CR¹³(R¹⁴)(R¹⁵)CR¹⁶(R¹⁷)(R¹⁸) where J is loweralkylene; or two adjacent groups selected from K, Z, D and E togetherwith the carbon atoms of the aryl ring to which they are attached form afurther phenyl ring, which is optionally substituted by one or moresubstituents selected from hydrogen, lower alkyl, halo, cyano, nitro,OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁵R²⁶, C(S)R²⁵R²⁶,SR²⁷ or C(O)SR²⁷; R¹ to R¹⁸ each independently is lower alkyl, aryl, Hetor at least one (CR^(x)R^(y)R^(z)) group attached to Q¹, Q² and/or Q³,i.e. CR¹R²R³, CR⁴R⁵R⁶, CR⁷R⁸R⁹, CR¹⁰R¹¹R¹², CR¹³R¹⁴R¹⁵, or CR¹⁶R¹⁷R¹⁸,is the group (Ad) wherein: Ad each independently is an optionallysubstituted adamantyl or congressyl radical bonded to the phosphorusatom via any one of its tertiary carbon atoms, the said optionalsubstitution being by one or more substituents selected from hydrogen,lower alkyl, halo, cyano, nitro, OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²²,NR²³R²⁴, C(O)NR²⁵ R²⁶, C(S)R²⁵R²⁶, SR²⁷ or C(O)SR²⁷; or if both(CR^(x)R^(y)R^(z)) groups attached to either or both Q¹ and/or Q², or Q³(if present) together with either Q¹ or Q² (or Q³) as appropriate, forman optionally substituted 2-phospha-tricyclo[3.3.1.1{3,7}]decyl group orderivative thereof, or form a ring system of formula

wherein R⁴⁹ and R⁵⁴ each independently is hydrogen, lower alkyl or aryl;R⁵⁰ to R⁵³, when present, each independently is hydrogen, lower alkyl,aryl or Het; and Y is oxygen, sulfur or N—R⁵⁵; and R⁵⁵, when present, ishydrogen, lower alkyl or aryl; R¹⁹ to R²⁷ each independently representis hydrogen, lower alkyl, aryl or Het; and Q¹, Q² and Q³ (when present)each independently is phosphorus, arsenic or antimony and in the lattertwo cases references to phosphorus above are amended accordingly.
 11. Aprocess as claimed in claim 10 wherein R¹ to R¹⁸ each independently islower alkyl, aryl, or Het.
 12. A process as claimed in claim 10 whereinsaid ligand is:(Ad)s(CR⁷R⁸R⁹)_(T)Q²-A-(K,D)Ar(E,Z)—B-Q¹(Ad)_(u)(CR¹R²R³)_(v), whereinK, D, E and Z is -J-Q³(Ad)_(w)(CR¹³(R¹⁴)(R¹⁵)_(x), wherein S and U are0, 1 or 2 provided that S+U≧1; wherein T and V are 0, 1 or 2 providedthat T+V≦3; and wherein W and X are 0, 1 or
 2. 13. A process as claimedin claim 1 wherein said ligand is of general formula (III):

wherein: A₁ and A₂, and A₃, A₄ and A₅ (when present), each independentlyis lower alkylene; K¹ is selected from the group consisting of hydrogen,lower alkyl, aryl, Het, halo, cyano, nitro, —OR¹⁹, —OC(O)R²⁰, —C(O)R²¹,—C(O)OR²², —N(R²³)R²⁴, —C(O)N(R²⁵)R²⁶, —C(S)(R²⁷)R²⁸, —SR²⁹, —C(O)SR³⁰,—CF₃ or -A₃-Q³(X⁵)X⁶; D¹ is selected from the group consisting ofhydrogen, lower alkyl, aryl, Het, halo, cyano, nitro, —OR¹⁹, —OC(O)R²⁰,—C(O)R²¹, —C(O)OR²², —N(R²³)R²⁴, —C(O)N(R²⁵)R²⁶, —C(S)(R²⁷)R²⁸, —SR²⁹,—C(O)SR³⁰, —CF₃ or -A₄-Q⁴(X⁷)X⁸; E¹ is selected from the groupconsisting of hydrogen, lower alkyl, aryl, Het, halo, cyano, nitro,—OR¹⁹, —OC(O)R²⁰, —C(O)R²¹, —C(O)OR²², —N(R²³)R²⁴, —C(O)N(R²⁵)R²⁶,—C(S)(R²⁷)R²⁸, —SR²⁹, —C(O)SR³⁰, —CF₃ or A₅-Q⁵(X⁹)X₁₀; or both D¹ and E¹together with the carbon atoms of the cyclopentadienyl ring to whichthey are attached form an optionally substituted phenyl ring: X¹ isCR¹(R²)(R³), congressyl or adamantyl, X² is CR⁴(R⁵)(R⁶), congressyl oradamantyl, or X¹ and X² together with Q² to which they are attached forman optionally substituted 2-phospha-tricyclo[3.3.1.1{3,7}]decyl group orderivative thereof, or X¹ and X² together with Q² to which they areattached form a ring system of formula IIIa

X³ is CR⁷(R⁸)(R⁹), congressyl or adamantyl, X⁴ is CR¹⁰(R¹¹)(R¹²),congressyl or adamantyl, or X³ and X⁴ together with Q¹ to which they areattached form an optionally substituted2-phospha-tricyclo[3.3.1.1{3,7}]decyl group or derivative thereof, or X³and X⁴ together with Q¹ to which they are attached form a ring system offormula IIIb

X⁵ is CR¹³(R¹⁴)(R¹⁵), congressyl or adamantyl, X⁶ is CR¹⁶(R¹⁷)(R¹⁸),congressyl or adamantyl, or X⁵ and X⁶ together with Q³ to which they areattached form an optionally substituted2-phospha-tricyclo[3.3.1.1{3,7}]decyl group or derivative thereof, or X⁵and X⁶ together with Q³ to which they are attached form a ring system offormula IIIc

X⁷ is CR³¹(R³²)(R³³), congressyl or adamantyl, X⁸ is CR³⁴(R³⁵)(R³⁶),congressyl or adamantyl, or X⁷ and X⁸ together with Q⁴ to which they areattached form an optionally substituted 2-phospha-tricyclo[3.3.1.1{3,7}]decyl group or derivative thereof, or X⁷ and X⁸ together with Q⁴to which they are attached form a ring system of formula IIId

X⁹ is CR³⁷(R³⁸)(R³⁹), congressyl or adamantyl, X¹⁰ is CR⁴⁰(R⁴¹)(R⁴²),congressyl or adamantyl, or X⁹ and X¹⁰ together with Q⁵ to which theyare attached form an optionally substituted2-phospha-tricyclo[3.3.1.1.{3,7}]decyl group or derivative thereof, orX⁹ and X¹⁰ together with Q⁵ to which they are attached form a ringsystem of formula IIIe

Q¹ and Q², and Q³, Q⁴ and Q⁵ (when present), each independently isphosphorus, arsenic or antimony; M is a Group VIB or VIIIB metal ormetal cation thereof; L₁ is an optionally substituted cyclopentadienyl,indenyl or aryl group; L₂ is one or more ligands each of which areindependently selected from hydrogen, lower alkyl, alkylaryl, halo, CO,P(R⁴³)(R⁴⁴)R⁴⁵ or N(R⁴⁶)(R⁴⁷)R⁴⁸; R¹ to R¹⁸ and R³¹ to R⁴², whenpresent, each independently is hydrogen, lower alkyl, aryl, halo or Het;R¹⁹ to R³⁰ and R⁴³ to R⁴⁸, when present, each independently is hydrogen,lower alkyl, aryl or Het; R⁴⁹, R⁵⁴ and R⁵⁵, when present, eachindependently is hydrogen, lower alkyl or aryl; R⁵⁰ to R⁵³, whenpresent, each independently is hydrogen, lower alkyl, aryl or Het; Y¹,Y², Y³, Y⁴ and Y⁵, when present, each independently is oxygen, sulfur orN—R⁵⁵; n=0 or 1; and m=0 to 5; provided that when n=1 then m equals 0,and when n equals 0 then m does not equal
 0. 14. A process as claimed inclaim 13 wherein if both K¹ is -A₃-Q³(X⁵)X⁶ and E¹ is A₅-Q⁵(X⁹)X¹⁰, thenD¹ is -A₄-Q⁴(X⁷)X⁸.
 15. A process as claimed in claim 10 or 13, whereinadamantyl is unsubstituted adamantyl or adamantyl substituted with oneor more unsubstituted C₁-C₈ alkyl substituents, or a combinationthereof.
 16. A process as claimed in claim 10 or 13, wherein2-phospha-adamantyl is unsubstituted 2-phospha-adamantyl or2-phospha-adamantyl substituted with one or more unsubstituted C₁-C₈alkyl substituents, or a combination thereof.
 17. A process as claimedin claim 10 or 13, wherein 2-phospha-adamantyl includes one or moreoxygen atoms in the 2-phospha-adamantyl skeleton.
 18. A process asclaimed in claim 10 or 13, wherein congressyl is unsubstitutedcongressyl.
 19. A process according to claim 1 wherein the palladium isin the metal form.
 20. A process according to claim 1, wherein thecatalyst system includes in a liquid reaction medium a polymericdispersant dissolved in a liquid carrier, said polymeric dispersantbeing capable of stabilising a colloidal suspension of particles of theGroup VI or VIIIB metal or metal compound of the catalyst system withinthe liquid carrier.
 21. A process according to claim 1, wherein thecarbonylation of ethene is performed in one or more aprotic solvents.22. A process according to claim 10, wherein Q¹, Q² and Q³ (whenpresent) is phosphorus.